CTM2 16 18 20 24 HP Onan Engines

User Manual: CTM2 - 16 18 20 24 HP Onan Engines

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CTM2 - 16 - 24 HP Onan Engines
- GROUP 00 - Introduction

16, 18, 20

and 24HP

Onan Engines

John Deere Horicon Works

CTM2 (19APR90)

LITHO IN U.S.A.

ENGLISH

This component technical manual (CTM) contains

necessary instructions to repair the engine.

Use this component technical manual in conjunction

with the machine technical manual. An engine

application listing in the introduction identifies

product-model/engine type-model relationship. See the

machine technical manual for:

• Engine removal and installation.

• Theory of operation, diagnostic, and testing

procedures.

NCAUTION: THIS SAFETY-ALERT

SYMBOL MEANS ATTENTION!

BECOME ALERT! YOUR SAFETY IS

INVOLVED.

When you see this symbol on your machine or in

your manual, be alert to the possibility of personal

injury or death. Follow the instructions in the safety

message.

CTM2,IFC -19-03FEB87

Introduction

CTM2 (19APR90) 16, 18, 20 & 24HP Onan Engines

130495

INTRODUCTION

This manual is part of a total service support program.

FOS MANUALS—REFERENCE

TECHNICAL MANUALS—MACHINE SERVICE

COMPONENT MANUALS—COMPONENT SERVICE

Fundamentals of Service (FOS) Manuals cover basic

theory of operation, fundamentals of troubleshooting,

general maintenance, and basic types of failures and

their causes. FOS Manuals are for training new

personnel and for reference by experienced technicians.

Technical Manuals are concise service guides for specific

machines. Technical manuals are on-the-job guides

containing only the vital information needed by an

experienced service technician.

Component Technical Manuals are concise service

guides for specific components. Component Technical

Manuals are written as stand alone manuals covering

multiple machine applications.

RW5559 -UN-23AUG88

O53,INTRO2 -19-03JUL85

Group 00

Introduction

CTM2 (19APR90) 00-1 16, 18, 20 & 24HP Onan Engines

130495

FEATURES OF THIS TECHNICAL MANUAL

John Deere ILLUSTRUCTION format emphasizing

illustrations and concise instructions in easy-to-use

modules.

Emphasis on diagnosis, analysis, and testing so you can

understand the problem and correct it.

Diagnostic information presented with the most logical

and easiest to isolate problems first to help you identify

the majority of routine failures quickly.

Step-by-step instructions for teardown and assembly.

Summary listing at the beginning of each group of all

applicable specifications, wear tolerances, torque values,

essential tools, and materials needed to do the job.

An emphasis throughout on safety—so you do the job

right without getting hurt.

This technical manual was planned and written for

you—an experienced service technician. Keep it in a

permanent binder in the shop where it is handy. Refer to

it when you need to know correct service procedures or

specifications.

RW5560 -UN-23AUG88

ABOUT THIS MANUAL

This Component Technical Manual (CTM-2) covers the

recommended repair procedures for all 16, 18, 20, and

24 HP Onan Engines removed from the machine. These

engines can be repaired on a clean work bench or put

on an engine stand.

Some components may be serviced without removing the

engine from the machine. You may want to determine

the repair procedure before you remove the engine.

Refer to the machine technical manual for engine

removal and installation procedures.

O53,INTRO3 -19-07OCT85

M98,INTR,1 -19-11NOV85

Introduction/About This Manual

CTM2 (19APR90) 00-2 16, 18, 20 & 24HP Onan Engines

130495

ENGINE SERIAL NUMBER PLATE

The engine serial number plate is located under the air

cleaner.

Refer to the engine model designation on your engine’s

serial number plate to identify repair information covered

in the Component Technical Manual.

M34584 -UN-07SEP88

BASIC ENGINE SPECIFICATIONS

ENGINE B43E B43G P218G B48G and P220G T260

CYLINDER 2 2 2 2 2

CYCLE 4 4 4 4 4

BORE 82.55 mm 82.55 mm 82.55 mm 82.55 mm 90.42 mm

(3.25 in.) (3.25 in.) (3.25 in.) (3.25 in.) (3.56 in.)

STROKE 66.55 mm 66.55 mm 73 mm 73 mm 76.20 mm

(2.62 in.) (2.62 in.) 2.875 in.) (2.87 in.) (3.00 in.)

DISPLACEMENT 710 cm3710 cm3782 cm3782 cm3983 cm3

(43.3 cu in.) (43 cu in.) 47.7 cu in.) (48 cu in.) (60 cu in.)

*HORSEPOWER 12kW (16 hp) 13.5 kW (18 HP) 13.4 kW 15 kW (20 hp) 18 kW (24 hp)

(18 hp)

*Horsepower rating is established by engine manufacturer in

accordance with Standard International Combustion Institute procedure.

It is corrected to (60 ˚F) and 29.92 hg barometer. Laboratory test

engines are equipped with air cleaner and muffler.

M98,INTR,2 -19-07OCT85

M98,INTR,3 -19-10FEB87

Introduction/Engine Specifications

CTM2 (19APR90) 00-3 16, 18, 20 & 24HP Onan Engines

130495

ENGINE APPLICATION CHART

Refer to the engine application chart to identify

product-model/engine type-model relationship.

CONSUMER PRODUCTS

Lawn and Garden Tractors

Machine No. Engine Model

316 . . . . . . . . . . . . . . . . . . . B43E or P218G

318 . . . . . . . . . . . . . . . . . . . B43G or P218G

420 . . . . . . . . . . . . . . . . . . . B48G or P220G

Front Mowers

Machine No. Engine Model

F910 . . . . . . . . . . . . . . . . . . B48G or P220G

F930 . . . . . . . . . . . . . . . . . . T260

ENGLISH TORQUE SPECIFICATIONS

NOTE: Wrench torque tolerance is ± 20%.

Bolt Three Six

Diameter Plain Head* Radial Dashes* Radial Dashes*

lb-ft N·m lb-ft N·m lb-ft N·m

1/4 in. 6 8 9 12 12 16

5/16 in. 10 14 18 24 25 34

3/8 in. 20 27 30 41 45 61

7/16 in. 30 41 50 68 70 95

1/2 in. 45 61 75 101 110 149

9/16 in. 70 95 110 150 155 210

5/8 in. 95 128 155 210 215 290

3/4 in. 165 225 270 365 385 520

7/8 in. 170 230 435 590 620 840

1 in. 255 345 660 895 930 1260

Torque figures indicated above and in the Specification Sections of this manual are valid for non-greased or

non-oiled threads and heads unless otherwise specified. Therefore, do not grease or oil bolts or cap screws

unless otherwise specified in this manual.

* Torque value for bolts and cap screws are identified by their head

markings.

M98,INTR,4 -19-29JAN87

S11,2000,DD -19-11JUL85

Introduction/Hardware Torque Specifications

CTM2 (19APR90) 00-4 16, 18, 20 & 24HP Onan Engines

130495

METRIC TORQUE SPECIFICATIONS

NOTE: Wrench torque tolerance is ± 20%.

Bolt Property Class 8.8* Property Class 10.9*

Diameter lb-ft N·m lb-ft N·m

M5 5 6 7 9

M6 8 10 11 15

M8 18 25 26 35

M10 37 50 52 70

M12 66 90 92 125

M16 166 225 229 310

M20 321 435 450 610

M24 554 750 775 1050

Torque figure indicated above and in the Specification Sections of this manual are valid for non-greased or

non-oiled threads and heads unless otherwise specified. Therefore, do not grease or oil bolts or cap screws

unless otherwise specified in this manual.

* Torque value for bolts and cap screws are identified by their head

markings. S11,2000,DE -19-11JUL85

Introduction/Hardware Torque Specifications

CTM2 (19APR90) 00-5 16, 18, 20 & 24HP Onan Engines

130495

Introduction/Hardware Torque Specifications

CTM2 (19APR90) 00-6 16, 18, 20 & 24HP Onan Engines

130495

SPECIFICATIONS

Item Measurement Specification

Breather Valve Cover Bolt Torque 2 ± 1 N·m (18 ± 9 lb-in.)

REMOVE AIR CLEANER

1. Remove wing nut and cover.

M36995 -UN-25JAN90

2. Remove lock nut and air cleaner element.

M36996 -UN-25JAN90

3. Remove precleaner. Wash precleaner as necessary.

M31044 -UN-14JUL89

M98,2005K,1 -19-07OCT85

M98,2005K,2 -19-07OCT85

M98,2005K,3 -19-07OCT85

M98,2005K,4 -19-07OCT85

Group 05

Air Cleaner and Breather

CTM2 (19APR90) 05-1 16, 18, 20 & 24HP Onan Engines

130495

4. Wash precleaner in warm, soapy water. Rinse in

clean water. Squeeze precleaner to remove most of

water. Let precleaner air dry.

M34579 -UN-07SEP88

5. Hold a lighted bulb inside air cleaner element. If you

can see the light through element and the paper appears

clean, the element is still usable. If the element is oily,

dirty, bent, torn, crushed or obstructed in any way, install

a new element.

M34582 -UN-07SEP88

IMPORTANT: Close choke and all openings to keep

objects from falling into carburetor,

flywheel housing, and air intake

system.

6. Remove three cap screws and splash plate (A).

7. Remove two base cap screws (B).

8. Push breather hose (C) from air cleaner base.

9. Lift air cleaner base from carburetor.

10. Clean inside of base and cover.

11. Inspect air intake hose for cracks or deterioration;

replace if necessary.

M36997 -UN-25JAN90

M98,2005K,5 -19-07OCT85

M98,2005K,6 -19-07OCT85

M98,2005K,7 -19-07OCT85

Air Cleaner and Breather/Air Cleaner

CTM2 (19APR90) 05-2 16, 18, 20 & 24HP Onan Engines

130495

INSTALL AIR CLEANER

1. Check carburetor intake to make sure the O-ring is in

place.

2. Put air cleaner base on carburetor.

3. Install breather hose (C). Be sure breather hose and

intake hose are tightly installed to prevent dirt from

entering the system.

4. Install and tighten two cap screws (B).

5. Install and fasten splash plate (A) with three screws.

M36997 -UN-25JAN90

6. Apply 1 oz (30 ml) of clean engine oil to precleaner.

7. Squeeze precleaner to distribute oil evenly and to

remove excess oil.

M34580 -UN-07SEP88

8. Put precleaner on air cleaner element. Install element

and holddown.

9. Install lock nut. Tighten until snug only.

M36996 -UN-25JAN90

M98,2005K,8 -19-08OCT85

M98,2005K,9 -19-08OCT85

M98,2005K,10 -19-11NOV85

Air Cleaner and Breather/Air Cleaner

CTM2 (19APR90) 05-3 16, 18, 20 & 24HP Onan Engines

130495

10. Install cover. Fasten with wing nut.

M36995 -UN-25JAN90

REPAIR BREATHER—T260 ENGINE

1. Remove air cleaner. (See Remove Air Cleaner in this

section.)

2. Loosen clamp to remove breather tube.

M36998 -UN-25JAN90

3. Remove filter packing.

4. Wash filter packing in a safe solvent and blow dry

with air pressure. If packing comes apart or is

deteriorated, replace it.

M36999 -UN-25JAN90

5. Wash breather valve with solvent.

Inspect ball valves to be sure they move freely.

Inspect O-ring for cuts or cracks. Replace if defective.

6. When installing breather tube, be sure filter packing is

in breather and that the O-ring is installed on the valve

assembly.

M37002 -UN-25JAN90

M98,2005K,11 -19-08OCT85

M98,2005K,12 -19-08OCT85

M98,2005K,13 -19-08OCT85

M98,2005K,14 -19-08OCT85

Air Cleaner and Breather/Breather, Repair

CTM2 (19APR90) 05-4 16, 18, 20 & 24HP Onan Engines

130495

REPAIR BREATHER—B43E, B43G, B48G,

P218G, AND P220G ENGINES

1. Remove air cleaner. (See Remove Air Cleaner in this

group.)

2. Pull breather tube from breather assembly.

M37000 -UN-25JAN90

3. Remove filter packing.

4. Wash filter packing in a safe solvent and blow dry

with air pressure. If packing comes apart or is

deteriorated, replace it.

M37001 -UN-25JAN90

5. Remove three cap screws to remove manifold cover.

M37017 -UN-25JAN90

6. Remove cap screw (A).

IMPORTANT: Do not drop small parts into engine

opening when removing breather

assembly.

7. Remove breather assembly.

M37018 -UN-25JAN90

M98,2005K,15 -19-29JAN87

M98,2005K,16 -19-08OCT85

M98,2005K,17 -19-08OCT85

M98,2005K,18 -19-08OCT85

Air Cleaner and Breather/Breather, Repair

CTM2 (19APR90) 05-5 16, 18, 20 & 24HP Onan Engines

130495

8. Clean parts with solvent. Inspect reed valve (C).

Replace it if cracked or bent. Replace gaskets if broken

or deteriorated.

NOTE: When installing the first gasket, be sure it aligns

with the flange on the deflector (B). Apply a small

amount of clean grease to the gaskets to hold

them in place during installation.

9. Install in order:

A—Gasket

B—Deflector

C—Reed Valve

D—Washer

E—Spring

F—Gasket

G—Valve Cover

H—Washer

I—Cap Screw

M37024 -UN-25JAN90

IMPORTANT: Be sure gaskets are in place before

tightening cap screw. Breather will not

function properly if air leaks are

present.

10. Tighten cap screw to 2 ± 1 N·m (18 ± 9 lb-in.).

M37025 -UN-25JAN90

11. Install manifold cover. Fasten with three cap screws.

M37017 -UN-25JAN90

M98,2005K,19 -19-08OCT85

M98,2005K,20 -19-11NOV85

M98,2005K,21 -19-11NOV85

Air Cleaner and Breather/Breather, Repair

CTM2 (19APR90) 05-6 16, 18, 20 & 24HP Onan Engines

130495

12. Install filter packing in breather tube.

M37001 -UN-25JAN90

13. Push breather tube securely onto valve cover.

M37000 -UN-25JAN90

M98,2005K,22 -19-11NOV85

M98,2005K,23 -19-11NOV85

Air Cleaner and Breather/Breather, Repair

CTM2 (19APR90) 05-7 16, 18, 20 & 24HP Onan Engines

130495

Air Cleaner and Breather/Breather, Repair

CTM2 (19APR90) 05-8 16, 18, 20 & 24HP Onan Engines

130495

SERVICE EQUIPMENT AND TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Name Use

Feeler Gauge Measure cylinder head flatness

SERVICE PARTS KITS

The following kits are available through your parts

catalog:

Overhaul Gasket Kit

M98,2010K,1 -19-11NOV85

M98,2010K,2 -19-08OCT85

Group 10

Intake Manifold and Cylinder Heads

CTM2 (19APR90) 10-1 16, 18, 20 & 24HP Onan Engines

130495

SPECIFICATIONS

Item Measurement Specification

MUFFLER AND EXHAUST PIPES

Exhaust Pipe Cap Screw

P218G, P220G, B43E, B43G, B48G Torque 11 ± 3 N·m 97 ± 27 lb-in.)

Engines

T260 Engine Torque 29 ± 2 N·m (257 ± 18 lb-in.)

Lift Bracket Cap Screw Torque 11 ± 3 N·m (97 ± 27 lb-in.)

INTAKE MANIFOLD

Attaching Cap Screw

B43E, B43G, B48G Engines Torque 11 ± 3 N·m (97 ± 27 lb-in.)

T260 Engine Torque 29 ± 2 N·m (257 ± 18 lb-in.)

P218G, P220G Engines Torque 6 N·m (53 lb-in.)

CYLINDER HEAD

Cylinder Head Flatness 0.005—0.10 mm (0.002—0.004 in.)

Attaching Cap Screws or Nuts

P218G, P220G, B43E, B43G, B48G Torque-In Sequence 20 ± 1 N·m (180 ± 12 lb-in.)

Engines

T260 Engine:

(Top six nuts with washers) Torque-In Sequence 16 ± 1 N·m (142 ± 12 lb-in)

(Bottom four nuts) Torque-In Sequence 20 ± 1 N·m (180 ± 12 lb-in.)

Lift Bracket Cap Screw Torque 11 ± 3 N·m (97 ± 27 lb-in.)

REMOVE INTAKE MANIFOLD

1. Remove muffler. (See machine technical manual.)

2. Remove four cap screws to remove exhaust pipes

and gasket (A). Inspect exhaust pipes for cracks or

damage. Replace as necessary.

3. Remove air cleaner base. (See Group 05 in this

manual.)

M36913 -UN-25JAN90

M98,2010K,3 -19-10FEB87

M98,2010K,4 -19-11NOV85

Intake Manifold and Cylinder Heads/Intake Manifold

CTM2 (19APR90) 10-2 16, 18, 20 & 24HP Onan Engines

130495

4. For T260 engines, remove two cap screws to remove

coil bracket.

5. Remove clip (A) to disconnect throttle rod.

M36920 -UN-25JAN90

6. If engine is in machine, loosen clamp and screw (A)

to disconnect choke cable (B).

7. If engine is in machine, slide hose clamp (C) back to

disconnect fuel inlet line (D).

A—Screw

B—Choke Cable

C—Hose Clamp

D—Fuel Inlet Line

M36921 -UN-25JAN90

8. For T260 engine, remove four cap screws to remove

intake manifold, carburetor, and gaskets (A).

For B43E, B43G, or B48G engine, remove three cap

screws to remove spacer (B), intake manifold, carburetor,

and gaskets (C).

For P218G and P220G engine, remove four cap screws

to remove intake manifold, carburetor, and gaskets.

T260 Engine

B43E, B43G, B48G Engines

M36922 -UN-25JAN90M36251 -UN-22NOV89

M98,2010K,5 -19-11NOV85

M98,2010K,6 -19-10FEB87

M98,2010K,7 -19-10FEB87

Intake Manifold and Cylinder Heads/Intake Manifold

CTM2 (19APR90) 10-3 16, 18, 20 & 24HP Onan Engines

130495

9. For T260, P218G or P220G engine, remove two cap

screws to remove carburetor, gasket (A), spacer (B), and

gasket (C).

For B43E, B43G, or B48G engine, remove two cap

screws to remove carburetor and gasket (A).

10. Inspect intake manifold for cracks or holes. Replace

as necessary.

T260, P218G, P220G Engine

B43E, B43G, B48G Engines

M36923 -UN-25JAN90M36252 -UN-22NOV89

INSTALL INTAKE MANIFOLD

1. Install a new gasket on intake manifold.

M36253 -UN-22NOV89

M98,2010K,8 -19-10FEB87

M98,2010K,9 -19-08OCT85

Intake Manifold and Cylinder Heads/Intake Manifold

CTM2 (19APR90) 10-4 16, 18, 20 & 24HP Onan Engines

130495

2. For T260, P218G, or P220G engine, install gasket (A)

spacer (B), gasket (C), and carburetor on intake

manifold. Install and tighten two cap screws.

For B43E, B43G, or B48G engine, install carburetor on

intake manifold and fasten with cap screws.

T260, P218G, P220G Engine

B43E, B43G, B48G Engines

M36924 -UN-25JAN90M36254 -UN-22NOV89

NOTE: For T260 engine, go to step 5.

3. Install new gaskets with notch in gasket aligned with

notch on intake port.

4. For B43E, B43G, or B48G engine, install intake

manifold and tighten cap screws to 11 ± 3 N·m (97 ± 27

lb-in.). Install spacer (A).

For P218G or P220G engine, install intake manifold and

oil fill tube. Tighten cap screws to 6 N·m (53 lb-in.).

M36255 -UN-29JAN90M36256 -UN-29JAN90

M98,2010K,10 -19-30JAN87

M98,2010K,11 -19-30JAN87

Intake Manifold and Cylinder Heads/Intake Manifold

CTM2 (19APR90) 10-5 16, 18, 20 & 24HP Onan Engines

130495

5. Install new gaskets on intake ports.

6. Install intake manifold and tighten cap screws to 29 ±

2 N·m (257 ± 18 lb-in.).

T260 engine

M36925 -UN-25JAN90M36926 -UN-25JAN90

7. If engine is in machine, connect fuel inlet line (D) and

fasten with hose clamp (C).

8. If engine is in machine, connect choke cable (B) to

choke linkage. Push choke knob down. Hold choke

linkage upward (choke plate open). Tighten screw (A)

and clamp.

A—Screw

B—Choke Cable

C—Hose Clamp

D—Fuel Inlet Line

M36921 -UN-25JAN90

9. Connect throttle rod and fasten with clip (A).

10. For T260 engine, install coil bracket on intake

manifold. Install and tighten two cap screws.

M36920 -UN-25JAN90

M98,2010K,12 -19-11NOV85

M98,2010K,13 -19-08OCT85

M98,2010K,14 -19-30JAN87

Intake Manifold and Cylinder Heads/Intake Manifold

CTM2 (19APR90) 10-6 16, 18, 20 & 24HP Onan Engines

130495

11. Install new exhaust pipe gaskets.

12. Install exhaust pipes and fasten with four cap

screws.

EXHAUST PIPE TORQUE SPECIFICATIONS

Engine Measurement Specifications

T260 Cap Screw Torque 29 ± 2 N·m

(257 ± 18 lb-in.)

B43E, B43G, B48G, Cap Screw Torque 11 ± 3 N·m

P218G or P220G (97 ± 27 lb-in.)

13. Install manifold covers and fasten with cap screws.

14. Install air cleaner assembly. (See Group 05 in this

manual.)

M36914 -UN-25JAN90M36915 -UN-25JAN90

M98,2010K,15 -19-10FEB87

Intake Manifold and Cylinder Heads/Intake Manifold

CTM2 (19APR90) 10-7 16, 18, 20 & 24HP Onan Engines

130495

REMOVE CYLINDER HEAD

1. Park tractor safely.

2. Remove engine. (See machine technical manual.)

3. Disconnect spark plug wire (A).

4. For T260 engine, remove six cap screws to remove

lift bracket (B), exhaust pipe shroud (C), and right side

shroud (D).

For B43E, B43G, or B48G engine, remove four cap

screws to remove lift bracket (B) and right side shroud

(D).

For P218G or P220G engines, remove air cleaner

assembly (See Group 05 in this manual.) Remove four

cap screws to remove lift bracket and right side shroud.

A—Spark Plug Wire

B—Lift Bracket

C—Exhaust Pipe Shroud

D—Right Side Shroud

T260 Engine

B43E, B43G, B48G Engines

M36927 -UN-25JAN90M36928 -UN-25JAN90

M98,2010K,17 -19-30JAN87

Intake Manifold and Cylinder Heads/Cylinder Head

CTM2 (19APR90) 10-8 16, 18, 20 & 24HP Onan Engines

130495

5. Disconnect spark plug wire (A).

6. For T260 engine, remove seven cap screws to

remove lift bracket (B), exhaust pipe shroud (C), and left

side shroud (D).

For B43E, B43G, OR B48G engine, disconnect voltage

regulator leads (E). Remove five cap screws to remove

lift bracket (B) and left side shroud (D).

For P218G or P220G engines, disconnect voltage

regulator leads. Remove four cap screws to remove lift

bracket and left side shroud.

A—Spark Plug Wire

B—Lift Bracket

C—Exhaust Pipe Shroud

D—Left Side Shroud

E—Voltage Regulator Leads

T260 Engine

B43E, B43G, B48G Engines

M36929 -UN-25JAN90M36930 -UN-25JAN90

M98,2010K,18 -19-10FEB87

Intake Manifold and Cylinder Heads/Cylinder Head

CTM2 (19APR90) 10-9 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Do not remove cylinder heads while

they are hot. Cylinder head may warp.

A hot gasket will be soft and difficult to

remove.

7. Remove spark plug (A).

8. For T260 engine, remove 10 nuts, 20 compression

washers (B), and 10 washers (C) to remove cylinder

head and gasket (D).

For P21G, P220G, B43E, B43G, OR B48G engine,

remove nine cap screws and washers (E) to remove T260 Engine

cylinder head and gasket (D).

A—Spark Plug

B—Compression Washer

(20 Used)

C—Washer (10 Used)

D—Gasket

E—Washer (9 Used)

P218G, P220G, B43E, B43G,B48G

M36931 -UN-25JAN90M36932 -UN-25JAN90

IMPORTANT: Do not damage gasket sealing surface

while cleaning carbon deposits.

9. Carefully clean carbon deposits from combustion

chamber and gasket surface on heads and cylinder block

with a scraper and wire brush.

10. Inspect head for cracks or broken cooling fins. Check

gasket sealing surface for burrs or nicks. Replace head if

damaged.

11. Measure cylinder head flatness in several locations.

CYLINDER HEAD SPECIFICATIONS

Item New Part Wear Tolerance

Flat Within 0.05 mm (0.002 in.) 0.10 mm (0.004 in.)

Replace head if cylinder head is warped more than 0.10

mm (0.004 in.).

M30948 -UN-14JUL89

M98,2010K,19 -19-10FEB87

M98,2010K,20 -19-08OCT85

Intake Manifold and Cylinder Heads/Cylinder Head

CTM2 (19APR90) 10-10 16, 18, 20 & 24HP Onan Engines

130495

INSTALL CYLINDER HEAD

NOTE: To install cylinder head on P218G, P220G, B43E,

B43G, OR B48G engine, go to step 4.

1. For T260 engine, install a new gasket (A) on cylinder

head.

2. Install cylinder head on cylinder block. Install flat

washer (B), two compression washers (C) with outside

edges contacting each other, and nut (D) on each of the

top six longer studs. Install flat washer and nut on each

of the bottom four shorter studs. Tighten nuts in several

steps in the sequence shown.

NUT TORQUE SPECIFICATIONS

Top six nuts . . . . . . . . . . . . . . . . . . . . 16 ± 1 N·m (142 ± 12 lb-in.)

(with compression washers)

Bottom four nuts . . . . . . . . . . . . . . . . . 20 ± 1 N·m (180 ± 12 lb-in.)

3. Install spark plug (E).

A—Gasket

B—Washer (10 Used)

C—Compression Washer (20 Used)

D—Nut (10 Used)

E—Spark Plug

M36933 -UN-25JAN90M36934 -UN-25JAN90

M98,2010K,21 -19-30JAN87

Intake Manifold and Cylinder Heads/Cylinder Head

CTM2 (19APR90) 10-11 16, 18, 20 & 24HP Onan Engines

130495

4. For P218G, P220G, B43E, B43G, or B48G engine,

install a new gasket (A) on cylinder head.

5. Install cylinder head on cylinder block with the five

longest cap screws in the top holes of cylinder head.

Tighten cap screws in several steps in the sequence

shown.

CAP SCREW TORQUE SPECIFICATION

Attaching Cap Screws . . . . . . . . . . . . . 20 ± 1 N·m (180 ± 12 lb-in.)

6. Install spark plug (B).

M36935 -UN-25JAN90M36936 -UN-25JAN90

M98,2010K,22 -19-30JAN87

Intake Manifold and Cylinder Heads/Cylinder Head

CTM2 (19APR90) 10-12 16, 18, 20 & 24HP Onan Engines

130495

7. For T260 engine, install left side shroud (D), exhaust

pipe shroud (C), lift bracket (B) and fasten with seven

cap screws. Tighten lift bracket cap screw to 11 ± 3 N·m

(97 ± 27 lb-in.).

For P218G or P220G engines, install left side shroud, lift

side shroud, lift bracket, and fasten with four cap screws.

Tighten lift bracket cap screw to 11 ± 3 N·m (97 ± 27

lb-in.). Connect voltage regulator leads.

For B43E, B43G, OR B48G engine, install left side

shroud (D), lift bracket (B), and fasten with five cap

screws. Tighten lift bracket cap screw to 11 ± 3 N·m (97

± 27 lb-in.).

Connect voltage regulator leads (E). Install the two stator

leads on “AC” terminals and the battery lead on “B+”

terminal of the voltage regulator.

8. Connect spark plug wire (A).

A—Spark Plug Wire

B—Lift Bracket

C—Exhaust Pipe Shroud

D—Left Side Shroud

E—Voltage Regulator Leads

T260 Engine

B43E, B43G, B48G Engines

M36929 -UN-25JAN90M36930 -UN-25JAN90

M98,2010K,23 -19-10FEB87

Intake Manifold and Cylinder Heads/Cylinder Head

CTM2 (19APR90) 10-13 16, 18, 20 & 24HP Onan Engines

130495

9. For T260 engine, install right side shroud (D), exhaust

pipe shroud (C), lift bracket (B), and fasten with six cap

screws. Tighten lift bracket cap screw to 11 ± 3 N·m (97

± 27 lb-in.).

For B43E, B43G, OR B48G engine, install right side

shroud (D), lift bracket (B), and fasten with four cap

screws. Tighten lift bracket cap screw to 11 ± 3 N·m (97

± 27 lb-in.).

For P218G or P220G engines, install right side shroud,

lift bracket, and fasten with four cap screws. Tighten lift

bracket cap screw to 11 ± 3 N·m (97 ± 27 lb-in.).

10. Connect spark plug wire (A).

11. Install engine. (See machine technical manual.)

A—Spark Plug Wire

B—Lift Bracket

C—Exhaust Pipe Shroud

D—Right Side Shroud

T260 Engine

B43E, B43G, B48G Engines

M36927 -UN-25JAN90M36928 -UN-25JAN90

M98,2010K,24 -19-10FEB87

Intake Manifold and Cylinder Heads/Cylinder Head

CTM2 (19APR90) 10-14 16, 18, 20 & 24HP Onan Engines

130495

ESSENTIAL TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Number Name Use

JDG 323 Valve Guide Driver Remove valve guides

JDE 118 Valve Guide Driver Remove valve guides

JDG 569 Valve Guide Installer Install valve guides

JDG 507 Valve Seat Cutter Cut seats to 45˚

SERVICE EQUIPMENT AND TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Name Use

Feeler Gauge Measure valve clearance

Valve Spring Compressor Remove and install valves

Valve Inspection Center Measure valve out-of-round

Outside Micrometer Measure valves and tappets

Spring Compression Tester Check valve springs

Valve Guide Brush Clean valve guides

Telescoping Gauge Measure tappet and valve guide bores

Valve Seat Cutter Recondition valve seats

Vernier Calipers Measure valve seat width

Blind Hole Puller Set Remove valve seats

Bushing, Bearing, and Seal Driver Set Install valve seats

M98,2015K,1 -19-10FEB87

M98,2015K,2 -19-11NOV85

Group 15

Intake and Exhaust Valves

CTM2 (19APR90) 15-1 16, 18, 20 & 24HP Onan Engines

130495

SERVICE PARTS KITS

The following kits are available through your parts

catalog:

Valve Gasket Kit

Tappet Kit

Overhaul Gasket Kit

M98,2015K,3 -19-08OCT85

Intake and Exhaust Valves/Service Parts Kits

CTM2 (19APR90) 15-2 16, 18, 20 & 24HP Onan Engines

130495

SPECIFICATIONS

Intake and Exhaust Valves (B43E, B43G, B48G, AND

T260 Engines)

Item New Specification Wear Tolerance

1. Exhaust Valve Stem O.D. 8.66—8.67 mm 8.64 mm (0.340 in.)

(0.341—0.3414 in.)

2. Intake Valve Stem O.D. 8.70—8.71 mm 8.66 mm (0.341 in.)

(0.3425—0.3429 in.)

3. Valve Face Angle 44˚

4. Valve Face Margin 0.787 mm (0.031 in.)

5. Valve Spring

Free length (approx.) 42.21 mm (1.662 in.)

Test length 34.92 mm (1.375 in.) at

169—187 N (38—42 lb force)

6. Valve Cover Cap Screw Torque 2.1 ± 0.7 N·m (18 ± 6 lb-in.)

Intake and Exhaust Valves (P218G and P220G Engines)

Item New Specification Wear Tolerance

1. Exhaust Valve Stem O.D. 7.061—7.074 mm 7.05 mm (0.2775 in.)

(0.2780—0.2785 in.)

2. Intake Valve Stem O.D. 7.099—7.112 mm 7.07 mm (0.2783 in.).

(0.2795—0.2800 in.)

3. Valve Face Angle 44˚

4. Valve Face Margin 0.787 mm (0.031 in.)

5. Valve Spring

Free length (approx.) 40.64 mm (1.60 in.)

Test length 26.67 mm (1.05 in.) at 245N

(55 lb force)

6. Valve Cover Cap Screw Torque 2.1 ± 0.7 N·m (18 ± 6 lb-in.)

M98,2015K,4 -19-10FEB87

Intake and Exhaust Valves/Specifications

CTM2 (19APR90) 15-3 16, 18, 20 & 24HP Onan Engines

130495

TAPPETS

Item New Specification Wear Tolerance

Tapped O.D. 18.99—19 mm 18.90 mm (0.744 in.) 2. Tappet Bore

(0.747—0.748 in.)

2. Tappet Bore I.D. 19.06—19.09 mm (0.750—0.751 in.) 19.15 mm (0.754 in.)

3. Tappet-To-Bore Clearance 0.04—0.08 mm (0.0015—0.003 in.) 0.15 mm (0.006 in.)

Valve Seats

Item New Specification Wear Tolerance

1. Valve Seat Angle 45˚

2. Valve Seat Width 0.8—1.2 mm (0.031—0.047 in.)

Valve Guides

Item New Specification Wear Tolerance

Valve Guide I.D. (B43E, 8.74—8.79 mm 8.84 mm (0.348 in.)

B43G, B48G, T260 Engines) (0.344—0.346 in.)

Valve Guide I.D. (P218G, 7.14—7.16 mm 7.19 mm (0.283 in.)

and P220G Engines) (0.281—0.282 in.)

2. Intake Valve Stem Clearance 0.03—0.06 mm 0.13 mm (0.005 in.)

(0.001—0.002 in.)

3. Exhaust Valve Stem Clearance 0.06—0.10 mm 0.15 mm (0.006 in.)

(0.002—0.004 in.)

Valve Clearance

Item New Specification Wear Tolerance

1. Intake Valve 0.13 mm (0.005 in.)

2. Exhaust Valve 0.33 mm (0.013 in.)

M98,2015K,5 -19-10FEB87

Intake and Exhaust Valves/Specifications

CTM2 (19APR90) 15-4 16, 18, 20 & 24HP Onan Engines

130495

REMOVE INTAKE AND EXHAUST VALVES

1. Remove engine if these components cannot be

removed with engine in unit. (See machine technical

manual.)

2. Remove exhaust pipes with muffler (A).

3. Remove intake manifold (B). (See Remove Intake

Manifold, Group 10 in this manual.)

4. Remove cylinder head (C). (See Remove Cylinder

Head, Group 10 in this manual.)

M36473 -UN-29JAN90

NOTE: Be careful not to lose breather assembly when

removing cover.

5. For P218G, P220G, B43E, B43G, OR B48G engines,

carefully remove cap screw to remove breather manifold

cover.

For T260 engine, remove cap screw to remove valve

cover and gasket (A).

B43E, B43G, B48G Engines

T260 Engine

M36262 -UN-29JAN90M36263 -UN-29JAN90

M98,2015K,6 -19-08OCT85

M98,2015K,7 -19-17FEB87

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-5 16, 18, 20 & 24HP Onan Engines

130495

6. Remove parts (A—F) if equipped and inspect for wear

or damage.

A—Spring

B—Washer

C—Valve

D—Gasket

E—Breather Base

F—Gasket

M36264 -UN-29JAN90

7. Close oil drain hole with a shop towel to prevent

retainers from falling into gear case.

IMPORTANT: Identify valve assembly during removal

so they can be installed in original

ports.

8. Compress valve springs using a valve spring

compressor to remove retainers. Release spring pressure

and remove compressor.

M36265 -UN-29JAN90

9. Remove exhaust and intake valves.

M36266 -UN-29JAN90

10. Clean carbon from valve face, head, and stem using

a wire brush.

11. Remove scratches from valve stems using steel wool

or crocus cloth.

12. Inspect valve for damage, corrosion, pitting, or

burned face.

13. Check valve for out-of-round, bent or warped

condition using a valve inspection center.

M35307 -UN-29AUG88

M98,2015K,8 -19-08OCT85

M98,2015K,9 -19-11NOV85

M98,2015K,10 -19-08OCT85

M98,2015K,11 -19-08OCT85

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-6 16, 18, 20 & 24HP Onan Engines

130495

14. Measure valve stem outside diameter.

B43E, B43G, B48G, AND T260

VALVE STEM SPECIFICATION

Item New Parts Wear Tolerance

Exhaust Valve 8.66—8.67 mm 8.64 mm

(0.341—0.3414 in.) (0.340 in.)

Intake Valve 8.70—8.71 mm 8.66 mm

(0.3425—0.3429 in.) (0.341 in.)

P21G AND P220G

VALVE STEM SPECIFICATIONS

Item New Parts Wear Tolerance

Exhaust Valve 7.061—7.074 mm 7.05 mm

(0.2780—0.2785 in.) (0.2775 in.)

Intake Valve 7.099—7.112 mm 7.07 mm

(0.2795—0.2800 in.) (0.2783 in.)

15. If diameter is less than wear tolerance specification,

replace valve.

M35308 -UN-29AUG88

IMPORTANT: Do not lap valves. The sharp seating

surface between the valve and seat will

be removed resulting in shorter valve

life.

16. If valve faces are worn, burned or pitted, grind

valves to a 44 degree face angle (A) following

manufacturers instructions. If valve face margin (B) is

less than 0.787 mm (0.031 in.) after grinding, replace

valve.

M36267 -UN-29AUG88

M98,2015K,12 -19-10FEB87

M98,2015K,13 -19-08OCT85

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-7 16, 18, 20 & 24HP Onan Engines

130495

17. Remove rotators (A) and springs (B) using a

screwdriver. Rotator must turn freely.

18. Check spring using a spring compression tester.

B43E, B43G, B48G AND T260

SPRING SPECIFICATIONS

Free length (approximate) . . . . . . . . . . . . . . . . 42.21 mm (1.662 in.)

Test length at 169—187 N . . . . . . . . . . . . . . . . . . . . . . . 34.92 mm

(38—42 lb force . . . . . . . . . . . . . . . . . . . 1.375 in.)

P218G AND P220G

SPRING SPECIFICATIONS

Free Length (approximate) . . . . . . . . . . . . . . . . 40.64 mm (1.60 in.)

Test length at 245N . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26.67 mm

(55 lb force . . . . . . . . . . . . . . . . . . . . . . . 1.05 in.)

M36268 -UN-29JAN90

IMPORTANT: Never reuse intake valve seal. The seal

must be replaced each time the valve is

removed.

19. Remove intake valve seal if equipped.

M36269 -UN-29JAN90

20. Remove tappets. Inspect tappets for wear or

damage.

M36270 -UN-29JAN90

M98,2015K,14 -19-10FEB87

M98,2015K,15 -19-08OCT85

M98,2015K,16 -19-08OCT85

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-8 16, 18, 20 & 24HP Onan Engines

130495

21. Measure tappet outside diameter.

TAPPET SPECIFICATIONS

Item New Parts Wear Tolerance

Tappet Diameter 18.99—19 mm 18.90 mm

(0.747—0.748 in.) (0.744 in.)

If tappet diameter is less than 18.90 mm (0.744 in.),

replace tappet.

M36272 -UN-29JAN90

22. Measure tappet bore inside diameter and determine

tappet clearance (tappet bore I.D. minus tappet O.D.).

TAPPET BORE SPECIFICATIONS

Item New Parts Wear Tolerance

Tappet Bore

Diameter 19.06—19.09 mm 19.15 mm

(0.750—0.751 in.) (0.754 in.)

Tappet Clearance 0.04—0.08 mm 0.15 mm

(0.0015—0.003 in.) (0.006 in.)

If tappet bore diameter exceeds 19.15 mm (0.754 in.),

install over-sized tappet or replace cylinder block.

If tappet clearance exceeds 0.15 mm (0.006 in.), install

over-sized tappet, replace tappet or replace cylinder

block.

NOTE: The over-sized tappets available are 0.05 mm

(0.002 in.) and 0.13 mm (0.005 in.).

M36273 -UN-29JAN90

23. Clean valve seats using a wire brush.

24. Inspect valve seats for damage, corrosion, pitting or

warped condition.

25. If necessary, cut seats to a 45 degree seat angle

using a seat cutter such as JDG507.

M36274 -UN-29JAN90

M98,2015K,17 -19-08OCT85

M98,2015K,18 -19-08OCT85

M98,2015K,19 -19-08OCT85

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-9 16, 18, 20 & 24HP Onan Engines

130495

26. Measure valve seat width after cutting. Valve seat

width must be 0.8—1.2 mm (0.031—0.047 in.).

27. If seat is too wide after cutting, use a 30 degree

valve seat cutter to narrow seat to specifications.

IMPORTANT: Do not lap valve seat. Doing so will

result in shorter valve life.

28. Clean the valve seats, valve guides, and valves with

solvent or a vacuum.

M36275 -UN-29JAN90

29. After valve grinding or seat cutting, check valves for

a tight and uniform seat.

Apply dye to valve face. Install and hold valve against

seat and turn slightly.

Remove valve and look for a fine clean line on valve

face. The line must be at the center of valve face and

have no open spots. If necessary, cut valve seat again

or replace valve seat.

M36276 -UN-29JAN90

30. Remove valve seats using a blind-hole puller.

M36952 -UN-25JAN90

M98,2015K,20 -19-08OCT85

M98,2015K,21 -19-08OCT85

M98,2015K,22 -19-08OCT85

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-10 16, 18, 20 & 24HP Onan Engines

130495

31. Clean valve guides using a valve guide brush.

32. Measure valve guide inside diameter and determine

valve stem clearance (valve guide I.D. minus valve stem

O.D.).

VALVE GUIDE SPECIFICATIONS

Item New Part Wear Tolerance

Valve Guide 8.74—8.79 mm 8.84 mm

Diameter (B43E, (0.344—0.346 in.) (0.348 in.)

B43G,B48G,T260

Valve Guide 7.14—7.16 mm 7.19 mm

Diameter P218G (0.281—0.282 in.) (0.283 in.)

and P220G)

Intake Valve 0.03—0.06 mm 0.13 mm

Stem Clearance (0.001—0.002 in.) (0.005 in.)

Exhaust Valve 0.06—0.10 mm 0.15 mm

Stem Clearance (0.002—0.004 in.) (0.006 in.)

If valve guide diameter exceeds specifications, replace

valve guide.

If valve stem clearance exceeds wear tolerance

specification, replace valve guide, valve, or both.

M36277 -UN-29JAN90

M98,2015K,23 -19-10FEB87

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-11 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Failure to lean top surface of valve

guide can damage valve guide bore

during removal.

33. Remove carbon from top surface of valve guide

using a wire brush.

34. For B43E, B43G, B48G or T260 engine, remove

valve guides using JDG 323 Valve Guide Driver.

For P218G or P220G engine, remove valve guides using

JDE 118 Valve Guide Driver.

35. Remove gasket (A).

M36278 -UN-29JAN90

INSTALL INTAKE AND EXHAUST VALVES

1. Clean and dry all parts. Apply clean engine oil to all

internal parts. Use a valve gasket kit when assembling

the engine.

2. Install a new gasket (A) on intake valve guide.

3. Install valve guides using JDG 569 Valve Guide

Installer (B) and a large washer (C). Pull valve guides

until shoulder is tight against cylinder block.

M36953 -UN-25JAN90

M98,2015K,24 -19-30JAN87

M98,2015K,25 -19-30JAN87

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-12 16, 18, 20 & 24HP Onan Engines

130495

4. Install valve seats with chamfer away from driver disk.

Push valve seats to bottom of cylinder block bore.

DISKS FOR VALVE SEAT INSTALLATION

Engine Valve Size

B43E, B43G, B48G Intake 1-3/16 and 1-7/16 in.

B43E, B43G, B48G Exhaust 15/16 and 1-3/16 in.

T260 Intake 1-1/8 and 1-1/2 in.

T260 Exhaust 1 and 1-5/16 in.

P218G, P220G Intake 1-7/16 in.

P218G, P220G Exhaust 1-3/16 in.

M36883 -UN-25JAN90

IMPORTANT: Valve assemblies must be installed in

original bores for maximum valve

performance.

5. Install tappets in original bores.

M36270 -UN-29JAN90

IMPORTANT: Never reuse intake valve seal. The seal

must be replaced each time the valve is

removed.

6. Install intake valve seal, if equipped, with lip of seal

toward tappet.

M36279 -UN-29JAN90

M98,2015K,26 -19-30JAN87

M98,2015K,27 -19-08OCT85

M98,2015K,28 -19-08OCT85

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-13 16, 18, 20 & 24HP Onan Engines

130495

7. Install springs (A) and rotators (B).

M36280 -UN-29JAN90

8. Put clean engine oil on valve stems.

9. Install intake and exhaust valves.

M36266 -UN-29JAN90

10. Close oil drain hole with a shop towel to prevent

retainers from falling into gear case.

11. Compress valve springs using a valve spring

compressor.

12. Apply petroleum jelly or retainers to help hold

retainers on valve stem. Install retainers on valve stem

with taper toward rotator. Be sure retainers are seated in

valve stem slot. Slowly release spring pressure to

remove compressor.

M36281 -UN-29JAN90

M98,2015K,29 -19-08OCT85

M98,2015K,30 -19-08OCT85

M98,2015K,31 -19-08OCT85

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-14 16, 18, 20 & 24HP Onan Engines

130495

MEASURE AND ADJUST VALVE

CLEARANCE

1. Turn the flywheel clockwise until the intake valve

opens and then closes. Continue turning flywheel until

the TDC (top-dead-center) mark (A) on the flywheel is

upward.

Both valves (B) must be closed and the piston (C) must

be at the top of its compression stroke. If the valves are

open, the piston is on the exhaust stroke and the

flywheel must be turned one revolution.

M36282 -UN-29JAN90M36283 -UN-29JAN90

2. Measure valve clearance using a feeler gauge.

VALVE CLEARANCE SPECIFICATION

Item Specification

Intake Valve (A) . . . . . . . . . . . . . . . . . . . . . . . 0.13 mm (0.005 in.)

Exhaust Valve (B) . . . . . . . . . . . . . . . . . . . . . . 0.33 mm (0.013 in.)

M36284 -UN-29JAN90

3. If necessary, hold tappet and turn tappet screw to

adjust valve clearance.

M36285 -UN-29JAN90

M98,2015K,32 -19-08OCT85

M98,2015K,33 -19-08OCT85

M98,2015K,34 -19-08OCT85

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-15 16, 18, 20 & 24HP Onan Engines

130495

CONTINUTE TO INSTALL AND EXHAUST

VALVES

1. Install parts (A—F) if equipped. Be sure washer (B) is

on top of valve (C).

A—Spring

B—Washer

C—Valve

D—Gasket

E—Breather Base

F—Gasket

M36264 -UN-29JAN90

NOTE: For T260 engine, go to Step 3.

2. Install breather manifold cover and cap screw. Check

that cap screw is installed through spring, washer, and

valve. Tighten cap screw to 2.1 ± 0.7 N·m (18 ± 6

lb-in.).

P218G, P220G, B43E, B43G, AND B48G

M36286 -UN-29JAN90M36287 -UN-29JAN90

3. Install new gasket (A). Install valve cover (B) and cap

screw. Tighten cap screw 2.1 ± 0.7 N·m (18 ± 6 lb-in.)

T260 Engine

M36288 -UN-29JAN90

M98,2015K,35 -19-11NOV85

M98,2015K,36 -19-10FEB87

M98,2015K,37 -19-11NOV85

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-16 16, 18, 20 & 24HP Onan Engines

130495

4. Install cylinder head (C). (See Install cylinder Head,

Group 10 in this manual.)

5. Install intake manifold (B). (See Install Intake Manifold,

Group 10 in this manual.)

6. Install exhaust pipes with muffler (A). (See Intake

Manifold, Group 10 in this manual.)

7. Install engine if removed. (See machine technical

manual.)

M36473 -UN-29JAN90

M98,2015K,38 -19-11NOV85

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-17 16, 18, 20 & 24HP Onan Engines

130495

Intake and Exhaust Valves/Intake and Exhaust Valves

CTM2 (19APR90) 15-18 16, 18, 20 & 24HP Onan Engines

130495

SERVICE EQUIPMENT AND TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Name Use

13-Ton Puller Set Remove flywheel

OTHER MATERIAL

Number Name Use

TY9375 John Deere LOCTITE® Pipe Apply to threads of flywheel cap

Sealant with TEFLON®screw

LOCTITE is a trademark of the Loctite Corp.

TEFLON is a trademark of the DuPont Co.

SPECIFICATIONS

Item Measurement Specification

B43E, B43G, B48G, and T260

Engine:

Flywheel Cap Screw Torque 51 ± 3 N·m (38 ± 2 lb-ft)

P218G and P220G Engine: Flywheel Torque 67—75 N·m (50—55 lb-ft)

Cap Screw

Lift Bracket Cap Screw Torque 11 ± 3 N·m (97 ± 27 lb-in.)

M98,2020K,1 -19-08OCT85

M98,2020K,1A -19-08OCT85

M98,2020K,2 -19-10FEB85

Group 20

Flywheel

CTM2 (19APR90) 20-1 16, 18, 20 & 24HP Onan Engines

130495

REMOVE FLYWHEEL

1. Remove engine. (See machine technical manual.)

2. Disconnect spark plug wire (A) and voltage regulator

leads (B).

3. Remove five cap screws (C) to remove lift bracket (D)

and right side shroud (E).

A—Spark Plug Wire

B—Voltage Regulator Leads

C—Cap Screw (5 used)

D—Lift Bracket

E—Right Side Shroud

M36289 -UN-29JAN90

4. Loosen hose clamp (A) to disconnect fuel pump

impulse line (B).

M36290 -UN-29JAN90

M98,2020K,3 -19-24OCT85

M98,2020K,4 -19-08OCT85

Flywheel/Flywheel

CTM2 (19APR90) 20-2 16, 18, 20 & 24HP Onan Engines

130495

5. Disconnect governor spring (A).

6. Remove two screws to remove fuel pump (B).

7. For P218 or P220G engines, remove air clean

assembly. Remove two cap screws to disconnect ignition

coil from flywheel shroud.

8. Disconnect fuel line.

9. Remove five cap screws to remove flywheel shroud

(C).

M36291 -UN-29JAN90

IMPORTANT: Do not use a pry bar in fins to keep

flywheel from turning. Doing so can

damage fins.

10. Fasten locking pliers to ring gear to prevent flywheel

from turning.

NCAUTION: Loosen flywheel cap screw only two

turns. Do not remove cap screw. If cap screw

is removed, flywheel may cause injury when it

comes loose.

11. Loosen cap screw two turns only.

M36292 -UN-29JAN90

M98,2020K,5 -19-30JAN87

M98,2020K,6 -19-30JAN87

Flywheel/Flywheel

CTM2 (19APR90) 20-3 16, 18, 20 & 24HP Onan Engines

130495

12. For P218G or P220G engines, remove two cap

screws from flywheel.

IMPORTANT: Do not pry on flywheel with a

screwdriver. Ceramic magnets on gear

case cover can be damaged.

13. Loosen flywheel using a puller.

14. Remove puller, cap screw, washer, and flywheel.

M36293 -UN-29JAN90

NOTE: P218G or P220G engine, flywheel and shield are

not shown.

15. If necessary, remove five cap screws to remove

flywheel shield.

16. Inspect flywheel for cracks, broken fins, or broken

magnets. Inspect flywheel ring gear for chipped or

broken teeth. Replace flywheel if damaged.

M36294 -UN-29JAN90

NOTE: Different engine models have different shaped

keys.

17. Remove key.

M36295 -UN-29JAN90

INSTALL FLYWHEEL

1. Install key in crankshaft.

For P218G or P220G engines, align slot in magnetic ring

with slot in crankshaft and install key.

M36296 -UN-29JAN90

M98,2020K,7 -19-30JAN87

M98,2020K,8 -19-30JAN87

M98,2020K,9 -19-10FEB87

M98,2020K,10 -19-30JAN87

Flywheel/Flywheel

CTM2 (19APR90) 20-4 16, 18, 20 & 24HP Onan Engines

130495

NOTE: P218G or P220G engine, flywheel and shield are

not shown.

2. Install flywheel shield, if removed, and fasten with five

cap screws.

M36294 -UN-29JAN90

IMPORTANT: Do not lubricate crankshaft taper. The

crankshaft taper must be dry to hold

the flywheel tight.

3. Clean crankshaft taper before installing flywheel.

4. Apply pipe sealant on threads of flywheel cap screw.

5. Align keyway (A) in flywheel with key (B) in

crankshaft. Install flywheel.

6. Install washer and cap screw.

7. Fasten locking pliers to ring gear to prevent flywheel

from turning.

8. On B43E, B43G, B48G, and T260 Engines: Tighten

cap screw to 51 ± 3 N·m (38 ± 2 lb-ft).

On P218G and P220G Engines: tighten cap screw to

67—75 N·m (50—55 lb-ft).

M36297 -UN-29JAN90M36298 -UN-29JAN90

M98,2020K,11 -19-30JAN87

M98,2020K,12 -19-10FEB85

Flywheel/Flywheel

CTM2 (19APR90) 20-5 16, 18, 20 & 24HP Onan Engines

130495

9. Install flywheel shroud (C) and fasten with five cap

screws.

10. For P218G or P220G engine, connect ignition coil to

flywheel shroud and fasten with two cap screws. Install

air cleaner assembly.

11. Connect fuel line to carburetor.

12. Install fuel pump (B) and fasten with two screws.

13. Connect governor spring (A) in top hole of arm.

M36291 -UN-29JAN90

14. Connect fuel pump impulse line (B) and fasten with

hose clamp (A).

M36290 -UN-29JAN90

M98,2020K,13 -19-30JAN87

M98,2020K,14 -19-30JAN87

Flywheel/Flywheel

CTM2 (19APR90) 20-6 16, 18, 20 & 24HP Onan Engines

130495

15. Install right side shroud (E), lift bracket (D) and

fasten with five cap screws (C). Tighten lift bracket cap

screw to 11 ± 3 N·m (97 ± 27 lb-in.).

16. Connect spark plug wire (A) and voltage regulator

leads (B). Install the two stator leads on “AC” terminals

and the battery lead on “B+” terminal of the voltage

regulator.

17. Install engine. (See machine technical manual.)

A—Spark Plug Wire

B—Voltage Regulator Leads

C—Cap Screw (5 used)

D—Lift Bracket

E—Right Side Shroud

M36289 -UN-29JAN90

M98,2020K,15 -19-30JAN87

Flywheel/Flywheel

CTM2 (19APR90) 20-7 16, 18, 20 & 24HP Onan Engines

130495

Flywheel/Flywheel

CTM2 (19APR90) 20-8 16, 18, 20 & 24HP Onan Engines

130495

ESSENTIAL TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Number Name Use

JDG 325 Crankshaft Seal Installer Install gear cover oil seal

SERVICE EQUIPMENT AND TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Name Use

Bushing, Bearing, and Seal Driver Set Remove and install oil seal, bearings, and

camshaft gear

Dial Indicator Measure camshaft gear end play and

backlash

Outside Micrometer Measure camshaft

Telescoping Gauge Measure camshaft bearings

Press Remove and install camshaft gear

OTHER MATERIAL

Number Name Use

TY6304 John Deere LOCTITE® Flexible Apply to camshaft plug surface of

Sealant cylinder block.

TY9375 John Deere LOCTITE Pipe Sealant Apply to threads of clutch adapter

with TEFLON®plate screws, gear cover cap

screws, and breaker point assembly

screw.

LOCTITE is a trademark of the Loctite Corp.

TEFLON is a trademark of the DuPont Co.

M98,2025K,1 -19-09OCT85

M98,2025K,2 -19-11NOV85

M98,2025K,2A -19-11NOV85

Group 25

Camshaft

CTM2 (19APR90) 25-1 16, 18, 20 & 24HP Onan Engines

130495

SERVICE PARTS KITS

The following kits are available through your parts

catalog:

Overhaul Gasket Kit

M98,2025K,2B -19-09OCT85

Camshaft/Service Parts Kits

CTM2 (19APR90) 25-2 16, 18, 20 & 24HP Onan Engines

130495

SPECIFICATION

Item New Specification Wear Tolerance

1. End Play: B43E, B43G, 0.08—0.3 mm 0.4 mm (0.018 in.)

B48G, and T260 Engine (0.003—0.012 in.)

End Play: P218G, P220G Engine0.280—1.22 mm 1.65 mm (0.065 in.)

(0.0110—0.0480 in.)

2. Gear Backlash:

B43E, B43G, B48G Engine 0.03—0.15 mm 0.23 mm (0.009 in.)

(0.001—0.006 in.)

T260 Engine 0.05—0.08 mm 0.15 mm (0.006 in.)

(0.002—0.003 in.)

P218G, P220 Engine 0.025—0.127 mm 0.20 mm (0.008 in.)

(0.001—0.005 in.)

3. Governor Cup Travel 5.6 mm (0.22 in.)

4. Journal O.D. 34.90—34.91 mm 34.80 mm (1.370 in.)

(1.374—1.375 in.)

5. Lobe Height:

Intake and Exhaust, B43E 28.37—28.47 mm 27.99 mm (1.102 in.)

(1.117—1.121 in.)

Intake, B43G, B48G 29.57—29.72 mm 29.18 mm (1.149 in.)

(1.164—1.170 in.)

Exhaust, B43G, B48G 29.44—29.59 mm 29.06 mm (1.144 in.)

(1.159—1.165 in.)

Intake and Exhaust, T260 29.57—29.72 mm 29.18 mm (1.149 in.)

(1.164—1.170 in.)

Intake, P218G 29 mm (1.142 in.) 28.49 mm (1.122 in.)

Exhaust, P218G 29.5 mm (1.162 in.) 28.98 mm (1.141 in.)

Intake, P220G 29.7 mm (1.171 in.) 29.18 mm (1.149 in.)

Exhaust, P220G 29.5 mm (1.162 in.) 28.98 mm (1.141 in.)

6. Bearing I.D. 34.95—34.98 mm 35.03 mm (1.379 in.)

(1.376—1.377 in.)

7. Camshaft Clearance 0.038—0.076 mm 0.125 mm (0.005 in.)

(0.0015—0.003 in.)

8. Clutch Adapter Plate 35 ± 1 N·m

Screw Torque (310 ± 9 lb-in.)

9. Gear Cover Cap Screws 12 ± 1 N·m

and Nut Torque (106 ± 9 lb-in.)

M98,2025K,3 -19-10FEB87

Camshaft/Specifications

CTM2 (19APR90) 25-3 16, 18, 20 & 24HP Onan Engines

130495

REMOVE CAMSHAFT

1. Remove engine. (See machine technical manual.)

2. Remove muffler and exhaust pipes (A).

3. Remove intake manifold (B). (See Remove Intake

Manifold, Group 10 in this manual.)

4. Remove cylinder heads (C). (See Remove Cylinder

Heads, Group 10 in this manual.)

5. Remove intake and exhaust valves (D). (See Remove

Intake and Exhaust Valves, Group 15 in this manual.)

6. Remove flywheel (E). (See Remove Flywheel, Group

20 in this manual.)

A—Muffler and Exhaust Pipes

B—Intake Manifold

C—Cylinder Heads

D—Intake and Exhaust Valves

E—Flywheel

M36474 -UN-29JAN90

7. Remove Allen screw to remove breaker point cover, if

equipped.

M36299 -UN-29JAN90

NOTE: Be careful not to lose the plunger during breaker

point assembly removal.

8. Remove two screws to remove breaker point

assembly and gasket (A), if equipped.

M36300 -UN-29JAN90

M98,2025K,4 -19-11NOV85

M98,2025K,5 -19-10FEB87

M98,2025K,6 -19-10FEB87

Camshaft/Camshaft

CTM2 (19APR90) 25-4 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Do not hit gear cover with a metal

hammer or remove cover with a

screwdriver. Doing so may damage

gear cover.

9. Remove four cap screws and nut to remove clip (A),

gear cover, and gasket (B).

For P218G or P220G engine, disconnect wire leads from

ignition coil. Remove crankshaft key and magnetic ring.

10. If gear cover is tight, hit cover lightly with a

soft-faced hammer to loosen it.

M36301 -UN-29JAN90

11. Remove oil seal using a 2 in. driver disk.

M36302 -UN-29JAN90

12. Measure camshaft end play.

CAMSHAFT END PLAY SPECIFICATION

Engine New Parts Wear Tolerance

B43E, B43G, B48G 0.08—0.3 mm 0.4 mm

and T260 (0.003—0.012 in.) (0.018 in.)

P218G and P220G 0.280—1.22 mm 1.65 mm

(0.0110—0.0480 in.) (0.065 in.)

If end play exceeds wear tolerance, replace camshaft

thrust washer.

M36303 -UN-29JAN90

M98,2025K,7 -19-10FEB87

M98,2025K,8 -19-09OCT85

M98,2025K,9 -19-02FEB87

Camshaft/Camshaft

CTM2 (19APR90) 25-5 16, 18, 20 & 24HP Onan Engines

130495

13. Measure camshaft gear backlash.

CAMSHAFT GEAR SPECIFICATIONS

Item New Part Wear Tolerance

B43E, B43G, B48G Engine

Camshaft Gear 0.03—0.15 mm 0.23 mm

Backlash (0.001—0.006 in.) (0.009 in.)

T260 Engine

Camshaft Gear 0.05—0.08 mm 0.15 mm

Backlash (0.002—0.003 in.) (0.006 in.)

P218G, P220G Engine

Camshaft Gear 0.025—0.127 mm 0.20 mm

Backlash (0.001—0.005 in.) (0.008 in.)

If backlash exceeds wear tolerance, replace camshaft

gear and crankshaft gear.

M36304 -UN-29JAN90

14. Remove snap ring to remove thrust washer.

M36305 -UN-29JAN90

IMPORTANT: Do not allow camshaft lobes to hit

bearing surfaces while removing

camshaft. Machined surfaces may be

damaged.

15. Carefully remove camshaft until rear lobe is even

with camshaft bearing. Turn camshaft until lobe (A) fits

into camshaft bearing notch (B). Remove camshaft.

M36307 -UN-29JAN90

M98,2025K,10 -19-10FEB87

M98,2025K,11 -19-09OCT85

M98,2025K,12 -19-09OCT85

Camshaft/Camshaft

CTM2 (19APR90) 25-6 16, 18, 20 & 24HP Onan Engines

130495

16. Remove thrust washer.

M36306 -UN-29JAN90

DISASSEMBLE AND INSPECT CAMSHAFT

1. Hold cup against flyballs. Measure distance from snap

ring to surface of hub. The distance must be 5.6 mm

(0.22 in.).

If the distance is not correct, replace camshaft assembly.

NOTE: The camshaft and pin are only serviced as an

assembly.

2. The cup (A) must spin freely on the camshaft pin

without excessive play. Replace parts as necessary.

M36308 -UN-29JAN90

3. Remove snap ring to remove hub (A) and cup (B).

4. Inspect cup race for grooved or rough surface.

Replace cup if necessary.

M36309 -UN-29JAN90

M98,2025K,13 -19-09OCT85

M98,2025K,14 -19-09OCT85

M98,2025K,15 -19-09OCT85

Camshaft/Camshaft

CTM2 (19APR90) 25-7 16, 18, 20 & 24HP Onan Engines

130495

5. Remove flyballs. Inspect flyballs for grooved or flat

spots, replace if necessary.

6. Inspect flyball spacer (A) for wear or damage.

Replace camshaft gear if necessary.

NOTE: The flyball spacer, plate, and camshaft gear are

serviced as an assembly only.

IMPORTANT: If camshaft gear is replaced, always

replace crankshaft gear also.

7. Inspect camshaft gear for chipped or broken teeth.

Replace camshaft gear if necessary.

M36310 -UN-29JAN90

IMPORTANT: Be sure to hold camshaft while

removing camshaft gear.

8. Remove gear using a 1 in. deep-well socket, 1 in.

driver disk, and a press.

9. Remove key.

M30688 -UN-14JUL89

10. Measure camshaft journal outside diameter.

CAMSHAFT JOURNAL SPECIFICATIONS

Item New Part Wear Tolerance

Journal Diameter 34.90—34.91 mm 34.80 mm

(1.374—1.3745 in.) (1.370 in.)

If journal diameter is less than 34.80 mm (1.370 in.),

replace camshaft.

M36311 -UN-29JAN90

M98,2025K,16 -19-09OCT85

M98,2025K,17 -19-11NOV85

M98,2025K,18 -19-11NOV85

Camshaft/Camshaft

CTM2 (19APR90) 25-8 16, 18, 20 & 24HP Onan Engines

130495

11. Measure camshaft lobe height.

CAMSHAFT LOBE SPECIFICATIONS

Item New Specification Wear Tolerance

Lobe Height:

B43E Intake and 28.37—28.47 mm 27.99 mm

Exhaust (1.117—1.121 in.) (1.102 in.)

B43G, B48G 29.57—29.72 mm 29.18 mm

Intake (1.164—1.170 in.) (1.149 in.)

B43G, B48G 29.44—29.59 mm 29.06 mm

Exhaust (1.159—1.165 in.) (1.144 in.)

T260 Intake and 29.57—29.72 mm 29.18 mm

Exhaust (1.164—1.170 in.) (1.149 in.)

P218G Intake 29 mm (1.142 in.) 28.49 mm

(1.122 in.)

P218G Exhaust 29.5 mm (1.162 in.) 28.98 mm

(1.141 in.)

P220G Intake 29.7 mm (1.171 in.) 29.18 mm

(1.149 in.)

P220G Exhaust 29.5 mm (1.162 in.) 28.98 mm

(1.141 in.)

If lobe height is less than wear tolerance, replace

camshaft.

M36312 -UN-29JAN90

12. If equipped, remove two screws to remove clutch

adapter plate.

M36313 -UN-29JAN90

M98,2025K,19 -19-02FEB87

M98,2025K,20 -19-09OCT85

Camshaft/Camshaft

CTM2 (19APR90) 25-9 16, 18, 20 & 24HP Onan Engines

130495

13. Remove plug (A) using a wooden dowel.

M36314 -UN-29JAN90

14. Measure camshaft bearing inside diameter and

determine camshaft clearance (camshaft bearing I.D.

minus camshaft journal O.D.).

CAMSHAFT BEARING SPECIFICATIONS

Item New Part Wear Tolerance

Camshaft Bearing 34.95—34.98 mm 35.03 mm

Diameter (1.376—1.377 in.) (1.379 in.)

Camshaft

Clearance 0.038—0.076 mm 0.125 mm

(0.0015—0.003 in.) (0.005 in.)

If camshaft bearing diameter exceeds 35.03 mm (1.379

in.) replace bearing.

If camshaft clearance exceeds 0.125 mm (0.005 in.),

replace camshaft bearing, camshaft, or both.

M36315 -UN-29JAN90

M98,2025K,21 -19-09OCT85

M98,2025K,22 -19-11NOV85

Camshaft/Camshaft

CTM2 (19APR90) 25-10 16, 18, 20 & 24HP Onan Engines

130495

15. Remove camshaft bearing using a soft steel rod or

chisel to bend bearing away from side of bore.

M36316 -UN-29JAN90M36317 -UN-29JAN90

ASSEMBLE CAMSHAFT

1. Install key in camshaft.

2. Install gear with timing mark “0” away from camshaft.

3. Align slot in gear with key in shaft.

4. Push camshaft into gear using a 1-3/8 in. driver disk

and a press until camshaft is even with bottom of gear

surface.

M30756 -UN-14JUL89

M98,2025K,23 -19-09OCT85

M98,2025K,24 -19-09OCT85

Camshaft/Camshaft

CTM2 (19APR90) 25-11 16, 18, 20 & 24HP Onan Engines

130495

5. Apply clean engine oil on camshaft parts before

assembly.

6. Install flyballs in flyball spacer (A) notches.

M36310 -UN-29JAN90

7. Install cup (A), hub (B), and fasten with snap ring.

M36318 -UN-29JAN90

8. Install thrust washer.

M36306 -UN-29JAN90

M98,2025K,25 -19-09OCT85

M98,2025K,26 -19-09OCT85

M98,2025K,27 -19-09OCT85

Camshaft/Camshaft

CTM2 (19APR90) 25-12 16, 18, 20 & 24HP Onan Engines

130495

INSTALL CAMSHAFT

1. Clean and dry all parts. Apply clean engine oil on all

internal parts before assembly.

NOTE: The service camshaft bearing is half the width of

the original bearing, but the camshaft bearing

surface is the same.

2. Align oil hole (A) in bearing with oil hole (B) in

cylinder block. Install rear bearing using a 1-3/8 in. driver

disk (C) and 1-1/2 in. driver disk (D). Push bearing even

with surface of cylinder block.

A—Bearing Oil Hole

B—Cylinder Block Oil Hole

C—1-3/8 in. Driver Disk

D—1-1/2 in. Driver Disk

M36319 -UN-29JAN90

3. Install front bearing using a 1-3/8 in. driver disk (A)

and 1-1/2 driver disk (B). Push bearing even with bottom

of bore. Be sure bearing is past breaker point plunger

hole (C) in cylinder block.

M36320 -UN-29JAN90

4. Apply flexible sealant on plug surface of cylinder

block.

5. Install plug tight against bottom of cylinder block

counterbore.

M36321 -UN-29JAN90

M98,2025K,28 -19-09OCT85

M98,2025K,29 -19-09OCT85

M98,2025K,30 -19-09OCT85

Camshaft/Camshaft

CTM2 (19APR90) 25-13 16, 18, 20 & 24HP Onan Engines

130495

6. If equipped, apply pipe sealant on threads of clutch

adapter plate screws.

7. Install clutch adapter plate and two screws. Tighten

screws to 35 ± 1 N·m (310 ± 9 lb-in.).

M36322 -UN-29JAN90

8. Put clean engine oil on camshaft bearing journals.

IMPORTANT: Do not allow camshaft lobe to hit

bearing surfaces while installing

camshaft. Machined surfaces may be

damaged.

9. Install flywheel cap screw in crankshaft to aid in

turning crankshaft for timing mark alignment.

10. Turn camshaft until lobe (A) fits into camshaft

bearing notch (B) and carefully install camshaft.

11. Align timing marks (C) on camshaft and crankshaft

gears and continue to install camshaft.

M36307 -UN-29JAN90M36323 -UN-29JAN90

M98,2025K,31 -19-09OCT85

M98,2025K,32 -19-09OCT85

Camshaft/Camshaft

CTM2 (19APR90) 25-14 16, 18, 20 & 24HP Onan Engines

130495

12. Align slot (A) in thrust washer with key (B) in

crankshaft.

13. Install thrust washer and snap ring.

M36324 -UN-29JAN90M36305 -UN-29JAN90

14. Install oil seal (A) with lip of seal downward, in gear

cover using JDG 325 Crankshaft Seal Installer (B).

M36325 -UN-29JAN90

15. Turn cup until the plastic bushing (A) is in the 3

o’clock position.

16. Apply multipurpose grease between cup and

camshaft gear to hold cup in position.

M36326 -UN-29JAN90

M98,2025K,33 -19-09OCT85

M98,2025K,34 -19-09OCT85

M98,2025K,35 -19-11NOV85

Camshaft/Camshaft

CTM2 (19APR90) 25-15 16, 18, 20 & 24HP Onan Engines

130495

17. Install new gasket on cylinder block.

18. Be sure plastic bushing (A) and pin (B) are aligned.

IMPORTANT: Do not hit gear cover with a metal

hammer during installation. Gear cover

may be damaged.

19. Hold governor arm away from camshaft and carefully

install gear cover.

M36327 -UN-29JAN90M36328 -UN-29JAN90

20. Pull engine forward and move governor arm back

and forth. Governor cup should be felt moving in and

out. If no movement is felt, the pin is not in plastic

bushing. Remove gear cover and repeat steps 18—20.

M36329 -UN-29JAN90

M98,2025K,36 -19-09OCT85

M98,2025K,37 -19-09OCT85

Camshaft/Camshaft

CTM2 (19APR90) 25-16 16, 18, 20 & 24HP Onan Engines

130495

21. Apply pipe sealant on cap screw (A) threads.

22. Install clip (B), four cap screws and nut. Tighten cap

screws and nut to 12 ± 1 N·m (106 ± 9 lb-in.).

23. Install stator wiring (C) in clip.

24. For P218G or P220G engine, connect wires leads to

ignition coil. Install crankshaft key and magnetic ring.

M36330 -UN-29JAN90

25. Install new gasket (A) on cylinder block.

NOTE: Be careful not to lose the plunger during breaker

point assembly installation.

26. Apply clean engine oil on plunger. Remove excess

oil after installation.

27. Apply pipe sealant on Allen screw threads.

28. Install breaker point assembly and fasten with two

Allen screws, if equipped.

M36331 -UN-29JAN90M36300 -UN-29JAN90

29. Install breaker point wire in breaker point assembly

groove.

20. Install breaker point cover and tighten Allen screw.

M36299 -UN-29JAN90

M98,2025K,38 -19-10FEB87

M98,2025K,39 -19-10FEB87

M98,2025K,40 -19-10FEB85

Camshaft/Camshaft

CTM2 (19APR90) 25-17 16, 18, 20 & 24HP Onan Engines

130495

31. Install flywheel (E). (See Group 20 in this manual.)

32. Install intake and exhaust valves (D). (See Install

intake and Exhaust Valves, Group 15 in this manual.)

33. Install cylinder heads (C). (See Install Cylinder

Heads, Group 10 in this manual.)

34. Install intake manifold (B). (See Install Intake

Manifold, Group 10 in this manual.)

35. Install engine. (See machine technical manual.)

A—Muffler and Exhaust Pipes

B—Intake Manifold

C—Cylinder Heads

D—Intake and Exhaust Valves

E—Flywheel

M36474 -UN-29JAN90

M98,2025K,41 -19-10FEB85

Camshaft/Camshaft

CTM2 (19APR90) 25-18 16, 18, 20 & 24HP Onan Engines

130495

SERVICE EQUIPMENT AND TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Name Use

Feeler Gauge Measure connecting rod end play and piston

ring end gap.

Ridge Reamer Remove ridge from top of cylinder bore.

Outside Micrometer Measure engine components.

Telescoping Gauge Measure connecting rod bores and piston pin

bore.

Piston Ring Expander Remove and install piston rings.

Vernier Calipers Measure piston ring groove width and piston

O.D.

Inside Micrometer Measure piston bore.

Flex Hone To deglaze cylinder bores

Piston Ring Compressor Install pistons in cylinder block.

OTHER MATERIAL

Number Name Use

PLASTIGAGE®Measure connecting rod bearing

clearance

PLASTIGAGE is a trademark of the TRW Corp.

SERVICE PARTS KITS

The following kits are available through your parts

catalog:

Overhaul Gasket Kit

M98,2030K,1 -19-11NOV85

M98,2030K,2 -19-09OCT85

M98,2030K,2A -19-11NOV85

Group 30

Connecting Rods and Pistons

CTM2 (19APR90) 30-1 16, 18, 20 & 24HP Onan Engines

130495

SPECIFICATIONS

Connecting Rods

Item New Specification Wear Tolerance

1. Side Clearance 0.05—0.41 mm 0.8 mm

(0.002—0.016 in.) (0.03 in.)

2. Connecting Rod Cap Nut Torque:

B43E, B43G, B48G, 18 ± 1 N·m

P218G, P220G Engine (159 ± 9 lb-in.)

3. Connecting Rod Cap Nut Torque:

T260 20 ± 1 N·m

(177 ± 9 lb-in.)

4. Piston Pin Clearance:

B43E, B43G, B48G Engine 0.005—0.010 mm

(0.0002—0.004 in.)

T260 Engine 0.003—0.013 mm

(0.001—0.005 in.)

P218G and P220G Engine 0.001—0.0162 mm

(0.00004—0.00064 in.)

5. Piston O.D.:

B43E, B43G, B48G, 82.42—82.44 mm 82.32 mm

P218G, P220G Engine (3.245—3.246 in.) (3.241 in.)

T260 Engine 90.42—90.45 mm 90.32 mm

(3.560—3.561 in.) (3.556 in.)

6. Cylinder Bore I.D.:

B43E, B43G, B48G, 82.53—82.55 mm 82.68 mm

P218G, P220G Engine (3.249—3.250 in.) (3.255 in.)

T260 Engine 90.488—90.512 mm 90.632 mm

(3.5625—3.5635 in.) (3.5682 in.)

7. Piston-To-Bore Clearance:

B43E, B43G, B48G, 0.076—0.127 mm 0.28 mm

P218G, P220G Engine (0.003—0.005 in.) (0.011 in.)

T260 Engine 0.178—0.229 mm 0.38 mm

(0.007—0.009 in.) (0.015 in.)

8. Cylinder Bore Taper:

B43E, B43G, B48G,

P218G, P220G Engine 0.13 mm (0.005 in.)

T260 Engine 0.08 mm (0.003 in.)

9. Cylinder Bore Out-of-Round 0.08 mm (0.003 in.)

M98,2030K,3 -19-11NOV85

Connecting Rods and Pistons/Specifications

CTM2 (19APR90) 30-2 16, 18, 20 & 24HP Onan Engines

130495

PISTON

Item New Specification Wear Tolerance

1. Ring Groove Width:

Top Ring 2.032—2.057 mm 2.21 mm

(0.080—0.081 in.) (0.087 in.)

Second Ring 2.032—2.057 mm 2.21 mm

(0.080—0.081 in.) (0.087 in.)

Oil Ring 4.775—4.801 mm 4.95 mm

(0.188—0.189 in.) (0.195 in.)

2. Ring End Gap 0.25—0.51 mm 1.52 mm

(0.010—0.020 in.) (0.060 in.)

3. Piston Pin Bore I.D.:

B43E, B43G, B48G, 17.468—17.478 mm

P218G, P220G Engine (0.6877—0.6881 in.)

T260 Engine 19.055—19.065 mm

(0.7502—0.7506 in.)

4. Rod-to-Crankshaft 0.051—0.084 mm 0.13 mm

Bearing Clearance (0.002—0.0033 in.) (0.0053 in.)

5. Crankshaft Connecting 41.28—41.30 mm 41.25 mm

Rod Journal O.D. (1.6252—1.6260 in.) (1.6242 in.)

6. Connecting Rod

Crankshaft Bore I.D.:

B43E, B43G, B48G, 41.35—41.36 mm 41.39 mm

P218G, P220G Engine (1.6280—1.6285 in.) (1.6295 in.)

T260 Engine 44.46—44.48 mm 44.50 mm

(1.7505—1.7510 in.) (1.7520 in.)

7. Piston Pin O.D.:

B43E, B43G, B48G, 17.463—17.468 mm 17.371 mm

P218G, P220G Engine (0.6875—0.6877 in.) (0.6839 in.)

T260 Engine 19.050—19.055 mm 18.959 mm

(0.7500—0.7502 in.) (0.7464 in.)

8. Connecting Rod

Piston Pin Bore I.D.:

B43E, B43G, B48G, 17.470—17.480 mm

P218G, P220G Engine (0.6878—0.6882 in.)

T260 19.06—19.07 mm

(0.7504—0.7508 in.)

9. Piston Pin Clearance:

B43E, B43G, B48G, 0.005—0.018 mm

P218G, P220G Engine (0.0002—0.00007 in.)

T260 Engine 0.005—0.020 mm

(0.0002—0.0008 in.)

M98,2030K,4 -19-11FEB87

Connecting Rods and Pistons/Specifications

CTM2 (19APR90) 30-3 16, 18, 20 & 24HP Onan Engines

130495

PISTON—CONTINUED

Item New Specification Wear Tolerance

10. Bores Out-of-Round 0.05 mm (0.002 in.)

Cylinder Head

Item New Specification

1. Attaching Cap Screw Torque:

B43E Engine 23 ± 1 N·m (204 ± 12 lb-in.)

B43G, B48G, P218G, P220G Engine 20 ± 1 N·m (180 ± 12 lb-in.)

2. Attaching Nut Torque (T260 Engine):

Top Six Nuts

(with compression washers) 16 ± 1 N·m (142 ± 12 lb-in.)

Bottom Four Nuts 20 ± 1 N·m (180 ± 12 lb-in.)

3. Oil Base Cap Screw Torque 27 ± 3 N·m (239 ± 27 lb-in.)

4. Lift Bracket Cap Screw Torque 11 ± 3 N·m (97 ± 27 lb-in.)

MEASURE CONNECTING ROD END PLAY

1. Remove engine. (See machine technical manual.)

2. Disconnect spark plug wire (A).

3. Remove six cap screws to remove lift bracket (B), oil

fill tube bracket (C), and left side shroud (D).

A—Spark Plug Wire

B—Lift Bracket

C—Oil Fill Tube Bracket

D—Left Side Shroud

M36472 -UN-29JAN90

M98,2030K,5 -19-02FEB87

M98,2030K,6 -19-09OCT85

Connecting Rods and Pistons/Connecting Rod

CTM2 (19APR90) 30-4 16, 18, 20 & 24HP Onan Engines

130495

4. Disconnect spark plug wire (A) and voltage regulator

leads (B).

5. Remove five cap screws (C) to remove lift bracket

(D), and right side shroud (E).

A—Spark Plug Wire

B—Voltage Regulator Leads

C—Cap Screw (5 used)

D—Lift Bracket

E—Right Side Shroud

M36289 -UN-29JAN90

6. Loosen hose clamp (A) to disconnect fuel pump

impulse line (B).

M36290 -UN-29JAN90

M98,2030K,7 -19-09OCT85

M98,2030K,8 -19-09OCT85

Connecting Rods and Pistons/Connecting Rod

CTM2 (19APR90) 30-5 16, 18, 20 & 24HP Onan Engines

130495

7. Disconnect governor spring (A).

8. Remove two screws to remove fuel pump (B).

9. Remove three cap screws to remove flywheel shroud

(C).

M36291 -UN-29JAN90

10. Remove four cap screws to remove oil base and

gasket (A).

M36374 -UN-29JAN90

11. Measure connecting rod side clearance. New side

clearance specification is 0.05—0.41 mm (0.002—0.016

in.).

If clearance exceeds 0.8 mm (0.03 in.), replace

connecting rod and connecting rod cap.

M36380 -UN-29JAN90

M98,2030K,9 -19-09OCT85

M98,2030K,10 -19-09OCT85

M98,2030K,11 -19-02FEB87

Connecting Rods and Pistons/Connecting Rod

CTM2 (19APR90) 30-6 16, 18, 20 & 24HP Onan Engines

130495

MEASURE CONNECTING ROD BEARING

CLEARANCE

Measure each connecting rod bearing clearance using

the following PLASTIGAGE method or by measuring

after the pistons have been removed.

IMPORTANT: Connecting rod end caps must be

installed on the same connecting rod

and in the same direction to prevent

crankshaft and connecting rod damage.

1. Put identification marks on connecting rods, rod caps,

and cylinder block.

2. Remove nuts to remove connecting rod caps (B43E,

B43G, B48G, P218G and P220G Engines—top photo).

Remove cap screws to remove connecting rod caps

(T260 Engine—bottom photo).

M36381 -UN-29JAN90M36388 -UN-29JAN90

3. Wipe oil from connecting rod bearing surface and

crankshaft journal.

4. Put a piece of PLASTIGAGE or an equivalent on the

full length of the bearing surface about 6 mm (1/4 in.) off

center.

M36382 -UN-29JAN90

M98,2030K,12 -19-02FEB87

M98,2030K,13 -19-09OCT85

Connecting Rods and Pistons/Connecting Rod

CTM2 (19APR90) 30-7 16, 18, 20 & 24HP Onan Engines

130495

5. Turn crankshaft about 30˚ from bottom of oil pan and

install connecting rod cap. Install and tighten nuts or cap

screws evenly to specifications.

CONNECTING ROD SPECIFICATIONS

Engine Measurement Specifications

B43E, B43G, B48G, Cap Nut Torque 18 ± 1 N·m

P218G, P220G (159 ± 9 lb-in.)

T260 Cap Screw Torque 20 ± 1 N·m

(177 ± 9 lb-in.)

M36383 -UN-29JAN90

6. Remove nuts or cap screws and connecting rod cap.

7. The flattened PLASTIGAGE will be found on either

the bearing surface or crankshaft journal.

8. Use the graduation marks on the envelope to

compare the width of the flattened PLASTIGAGE at its

WIDEST point. Remove PLASTIGAGE.

The number within the graduation marks indicates the

bearing clearance in thousandths of an inch or in

millimeters depending on which side of the envelope is

used.

9. New bearing clearance is 0.051—0.084 mm

(0.002—0.0033 in.).

If clearance exceeds 0.13 mm (0.0053 in.), remove

pistons.

If clearance is correct, install connecting rod caps and

tighten nuts or cap screws to specifications.

M36384 -UN-29JAN90

M98,2030K,14 -19-02FEB87

M98,2030K,15 -19-09OCT85

Connecting Rods and Pistons/Connecting Rod

CTM2 (19APR90) 30-8 16, 18, 20 & 24HP Onan Engines

130495

REMOVE PISTONS AND CONNECTING

RODS

1. Remove engine. (See machine technical manual.)

2. Disconnect spark plug wire (A).

3. Remove six cap screws to remove lift bracket (B), oil

fill tube (C), and left side shroud (D).

A—Spark Plug Wire

B—Lift Bracket

C—Oil Fill Tube Bracket

D—Left Side Shroud

M36472 -UN-29JAN90

4. Disconnect spark plug wire (A) and voltage regulator

leads (B).

5. Remove five cap screws (C) to remove lift bracket

(D), and right side shroud (E).

A—Spark Plug Wire

B—Voltage Regulator Leads

C—Cap Screw (5 used)

D—Lift Bracket

E—Right Side Shroud

M36289 -UN-29JAN90

M98,2030K,16 -19-09OCT85

M98,2030K,7 -19-09OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-9 16, 18, 20 & 24HP Onan Engines

130495

6. Loosen hose clamp (A) to disconnect fuel pump

impulse line (B).

M36290 -UN-29JAN90

7. Disconnect governor spring (A).

8. Remove two screws to remove fuel pump (B).

9. Remove three cap screws to remove flywheel shroud

(C).

M36291 -UN-29JAN90

10. Remove four cap screws to remove oil base and

gasket (A).

M36374 -UN-29JAN90

M98,2030K,8 -19-09OCT85

M98,2030K,9 -19-09OCT85

M98,2030K,10 -19-09OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-10 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Do not remove cylinder heads while

they are hot. Cylinder head may warp.

A hot gasket will be soft and difficult to

remove.

11. Remove nine cap screws to remove cylinder head

and gasket (A).

Remove 10 nuts, 20 compression washers (A), and ten

washers (B) to remove cylinder head and gasket (C).

B43E,B43G,B48G,P21G and P220G

T260 Engine

M36385 -UN-29JAN90M36386 -UN-29JAN90

12. Clean carbon from cylinder bore using a wire brush.

13. Before piston removal, check cylinder bore for ridges.

The ridges can cause damage to piston or rings if ridge

is not removed.

14. If necessary, remove ridge from top of cylinder bore

using a ridge reamer.

M36387 -UN-29JAN90

M98,2030K,17 -19-02FEB87

M98,2030K,18 -19-09OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-11 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Connecting rod caps must be installed

on the same connecting rod and in the

same direction to prevent crankshaft

and connecting rod damage.

15. Put identification marks on connecting rods, rod

caps, and cylinder block.

16. Remove nuts to remove connecting rod caps. (B43E,

B43G, B48G, P218G and P220G Engines—top photo.)

Remove cap screws to remove connecting rod caps.

(T260 Engine-bottom photo)

M36381 -UN-29JAN90M36388 -UN-29JAN90

17. Push piston and connecting rod out of cylinder bore

using a wooden dowel.

M36389 -UN-29JAN90

M98,2030K,19 -19-02FEB87

M98,2030K,20 -19-09OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-12 16, 18, 20 & 24HP Onan Engines

130495

INSPECT PISTONS AND CONNECTING

RODS

1. Measure crankshaft connecting rod journal diameter.

Measure several places around each journal and each

side of journal.

NOTE: If engine has had previous major overhaul,

crankshaft journals may have been ground and

undersize connecting rods installed.

CONNECTING ROD JOURNAL SPECIFICATIONS

Item New Parts Wear Tolerance

Journal O.D. 41.28—41.30 mm 41.25 mm

(1.6252—1.6260 in.) (1.6242 in.)

If journal diameter is less than 41.25 mm (1.6242 in.),

replace crankshaft or have journals ground by a qualified

machine shop. The following undersize connecting rods

are available:

0.25 mm (0.010 in.)

0.50 mm (0.020 in.)

0.76 mm (0.030 in.)

M36390 -UN-29JAN90

M98,2030K,21 -19-11NOV85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-13 16, 18, 20 & 24HP Onan Engines

130495

2. Measure connecting rod bore diameter and connecting

rod clearance (bore I.D. minus journal O.D.).

3. Install connecting rod cap on connecting rod. Install

and tighten nuts or cap screws evenly to specifications.

CONNECTING ROD SPECIFICATIONS

Cap Nut Torque

B43E, B43G, B48G,

P218G, P220G

Engines 18 ± 1 N·m (159 ± 9 lb-in.)

Cap Screw Torque

T260 Engine 20 ± 1 N·m (177 ± 9 lb-in.)

Item New Parts Wear Tolerance

Bore I.D.:

B43E,B43G,B48G,

P218G, P220G 41.35—41.36 mm 41.39 mm

Engines (1.6280—1.6285 in.) (1.6295 in.)

T260 Engine 44.46—44.48 mm 44.50 mm

(1.7505—1.7510 in.) (1.7520 in.)

Clearance 0.051—0.084 mm 0.135 mm

(0.0020—0.0033 in.) (0.0053 in.)

If bore diameter exceeds wear tolerance, replace

connecting rod.

If connecting rod clearance exceeds 0.135 mm (0.0053

in.), replace connecting rod or grind crankshaft

connecting rod journals and install undersize connecting

rods.

M36391 -UN-29JAN90

4. Remove piston rings using a piston ring expander.

IMPORTANT: Do not use a caustic cleaning solvent

to remove carbon from pistons; piston

may be damaged.

5. Clean carbon from piston surfaces using a wire brush.

Clean piston ring grooves with a piston ring groove

cleaner or the end of a piston ring filed to a sharp point.

M36392 -UN-29JAN90

M98,2030K,22 -19-02FEB87

M98,2030K,23 -19-09OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-14 16, 18, 20 & 24HP Onan Engines

130495

6. Measure piston ring groove width. Measure several

places around each piston.

PISTON RING GROOVE SPECIFICATIONS

Item New Part Wear Tolerance

Top Ring 2.032—02.057 mm 2.21 mm

(0.080—0.081 in.) (0.087 in.)

Second Ring 2.032—2.057 mm 2.21 mm

(0.080—0.081 in.) (0.087 in.)

Oil Ring 4.775—4.801 mm 4.95 mm

(0.188—0.189 in.) (0.195 in.)

If ring groove width exceeds wear tolerance, replace

piston.

M36393 -UN-29JAN90

7. Inspect piston for worn or cracked ring lands.

Excessive piston wear near the edge of the top ring land

indicated preignition.

8. Clean and inspect oil holes in oil ring groove for a

plugged condition. Replace parts as necessary.

M36394 -UN-29JAN90

M98,2030K,24 -19-11NOV85

M98,2030K,25 -19-09OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-15 16, 18, 20 & 24HP Onan Engines

130495

9. Measure piston ring end gap. Push rings into cylinder

bore approximately halfway using piston.

PISTON RING END GAP SPECIFICATIONS

Item New Part Wear Tolerance

All Rings 0.25—0.51 mm 1.52 mm

(0.010—0.020 in.) (0.060 in.)

If end gap exceeds 1.52 mm (0.060 in.), replace rings.

Deglaze cylinder bore before installing new rings.

M36395 -UN-29JAN90M36396 -UN-29JAN90

IMPORTANT: Pistons must be installed in the same

direction and on the same connecting

rod they were removed from.

10. Put a mark on each piston and connecting rod for

proper identification to aid in assembly.

11. Remove two snap rings.

12. Remove piston pin using a wooden dowel.

M36397 -UN-29JAN90

M98,2030K,26 -19-12NOV85

M98,2030K,27 -19-09OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-16 16, 18, 20 & 24HP Onan Engines

130495

13. Measure diameter of piston pin at six places; two

measurements 90˚ apart at each end and two

measurements 90˚ at center.

PISTON PIN SPECIFICATIONS

Item New Part Wear Tolerance

Pin O.D.

B43E,B43G,B48G,

P218G, P220G 17.463—17.468 mm 17.371 mm

Engine (0.6875—0.6877 in.) (0.6839 in.)

T260 Engine 19.050—19.055 mm 18.959 mm

(0.7500—0.7502 in.) (0.7464 in.)

If pin diameter is less than wear tolerance, install a new

piston pin.

M35365 -UN-29AUG88

14. Measure piston pin bore in connecting rod and piston

pin clearance (bore I.D. minus pin O.D.).

PISTON PIN BORE SPECIFICATIONS

Engine Item New Part

B43E, B43G, B48G, Bore I.D. 17.470—17.480 mm

P218G, P220G (0.6878—0.6882 in.)

B43E, B43G, B48G, Pin Clearance 0.005—0.018 mm

P218G, P220G (0.0002—0.0007 in.)

T260 Bore I.D. 19.06—19.07 mm

(0.7504—0.7508 in.)

T260 Pin Clearance 0.005—0.020 mm

(0.0002—0.0008 in.)

If piston pin bore diameter exceeds specifications,

replace connecting rod.

If pin clearance exceeds specifications, replace

connecting rod, piston pin, or both.

15. Inspect connecting rod cap screws and nuts for

damaged threads. Inspect connecting rods for nicks,

cracks, scored bores, or bores out-of-round more than

0.05 mm (0.002 in.).

M36398 -UN-29JAN90

M98,2030K,28 -19-02FEB87

M98,2030K,29 -19-11FEB87

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-17 16, 18, 20 & 24HP Onan Engines

130495

16. Measure piston pin bore in piston and piston pin

clearance (bore I.D. minus pin O.D.).

PISTON PIN BORE SPECIFICATIONS

Engine Item New Part

B43E, B43G, B48G, Bore I.D. 17.468—17.478 mm

P218G, P220G (0.6877—0.6881 in.)

B43E, B43G, B48G Pin Clearance 0.005—0.010 mm

(0.002—0.0004 in.)

P218G, P220G 0.001—0.0162 mm

(0.00004—0.00064 in.)

T260 Bore I.D. 19.005—19.065 mm

(0.7502—0.7506 in.)

T260 Pin Clearance 0.003—0.013 mm

(0.0001—0.0005 in.)

If piston pin bore diameter exceeds specifications,

replace piston.

If piston pin clearance exceeds specifications; replace

piston, piston pin, or both.

M36399 -UN-29JAN90

M98,2030K,30 -19-11FEB87

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-18 16, 18, 20 & 24HP Onan Engines

130495

17. Measure piston O.D. perpendicular to piston bore at

a point approximately 30 mm (1.2 in.) from top of piston

or 2.5 mm (0.1 in.) below oil ring groove.

NOTE: If engine has had a previous major overhaul,

oversize pistons and rings may have been

installed.

PISTON SPECIFICATIONS

Item New Part Wear Tolerance

Piston O.D.

B43E, B43G, B48G,

P218G, P220G 82.42—82.44 mm 82.32 mm

Engine (3.245—3.246 in.) (3.241 in.)

T260 Engine 90.42—90.45 mm 90.32 mm

(3.560—3.561 in.) (3.556 in.)

If piston diameter is less than wear tolerance, install a

new piston.

18. Inspect piston for cracks at ring lands, skirts, and pin

bores. Inspect piston for scuffing or scoring; replace as

necessary.

M36400 -UN-29JAN90

19. Inspect cylinder bores for scuffing, scoring, scratches,

cracks, and wear. If cylinder bores are damaged, replace

cylinder block or rebore and hone cylinder for next

oversize piston.

20. If the cylinder bore is not damaged, check cylinder

bore for wear.

M36401 -UN-29JAN90

M98,2030K,31 -19-02FEB87

M98,2030K,32 -19-09OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-19 16, 18, 20 & 24HP Onan Engines

130495

21. Measure piston bore I.D. at four places; two

measurements 90˚ apart at top of ring travel and two

measurements 90˚ apart at bottom of ring travel.

NOTE: If engine has had a previous major overhaul,

oversize pistons and rings may have been

installed.

22. Measure piston clearance (piston bore I.D. minus

piston O.D.).

23. Measure cylinder bore taper (A—C, B—D).

24. Measure cylinder bore out-of round (A—B, C—D).

CYLINDER BORE SPECIFICATIONS

Item New Part Wear Tolerance

Bore I.D.

B43E,B43G, B48G,

P218G, P220G 82.53—82.55 mm 82.68 mm

Engine (3.249—3.250 in.) (3.255 in.)

T260 Engine 90.488—90.512 mm 90.632 mm

(3.5625—3.5635 in.) (3.5682 in.)

Piston Clearance

B43E, B43G, B48G,

P218G, P220G 0.076—0.127 mm 0.28 mm

Engine (0.003—0.005 in.) (0.011 in.)

T260 Engine 0.178—0.229 mm 0.38 mm

(0.007—0.009 in.) (0.015 in.)

Taper

B43E, B43G, B48G,

P218G, P220G 0.13 mm

Engine (0.005 in.)

T260 Engine 0.08 mm

(0.003 in.)

Out-of-Round 0.08 mm

(0.003 in.)

If cylinder bore exceeds wear tolerance, replace cylinder

block or have cylinder rebored by a qualified machine

shop. If cylinder is rebored, oversize piston and rings

must be installed. The following oversize pistons and

rings are available:

0.25 mm (0.010 in.)

0.50 mm (0.020 in.)

0.76 mm (0.030 in.)

If piston clearance exceeds wear tolerance, replace

cylinder block, piston or both, or rebore cylinder. Install

oversize piston and rings.

If taper or out-of-round exceed wear tolerance, replace

cylinder block, or rebore cylinder. Install oversize piston

and rings.

M36402 -UN-29JAN90

M98,2030K,33 -19-11FEB87

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-20 16, 18, 20 & 24HP Onan Engines

130495

DEGLAZE CYLINDER BORES

NOTE: It is recommended that crankshaft be removed. If

cylinder bores are to be deglazed with crankshaft

installed in engine, put clean shop towels over

crankshaft to protect journal and bearing surfaces

from any abrasives.

1. Deglaze cylinder bores using a flex-hone.

M36403 -UN-29JAN90

NOTE: A cutaway of a cylinder bore is shown for clarity

of photograph.

2. Use flex-hone as instructed by manufacturer to obtain

45˚ crosshatch pattern as shown.

IMPORTANT: Do not use gasoline, kerosene, or

commercial solvents to clean cylinder

bores. Solvents will not remove all

abrasives from cylinder walls.

3. Remove excess abrasive residue from cylinder walls

using a clean dry rag. Clean cylinder walls using clean

white rags and water. Continue to clean cylinder until

white rags show no discoloration.

RW619 -UN-02DEC88

ASSEMBLE PISTONS AND CONNECTING

RODS

IMPORTANT: Pistons must be installed on

connecting rods from which they were

removed.

1. Identification marks on piston must be to the same

side as marks on connecting rod.

2. Put clean engine oil on piston pin. Install pin through

piston and connecting rod.

3. Install snap rings. Be sure snap rings are fastened in

groove all around.

M36397 -UN-29JAN90

M98,2030K,34 -19-10OCT85

M98,2025R,29 -19-31JUL84

M98,2030K,35 -19-10OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-21 16, 18, 20 & 24HP Onan Engines

130495

4. Install oil ring expander in bottom piston ring groove.

Turn expander so ends are above either end of the

piston pin.

5. Install oil ring over expander with a piston ring

expander. Turn oil ring so ends are on opposite side of

piston from the expander ends.

M36392 -UN-29JAN90

6. Install second ring in middle groove, with chamfer (A)

toward bottom of piston, or with dot (B) toward top of

piston (T260 only).

7. Install compression ring in top groove, with dot (B)

toward top of piston.

M36406 -UN-29JAN90M36404 -UN-29JAN90

M98,2030K,36 -19-10OCT85

M98,2030K,37 -19-10OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-22 16, 18, 20 & 24HP Onan Engines

130495

INSTALL PISTONS AND CONNECTING

RODS

IMPORTANT: Pistons must be installed in the same

cylinder they were removed from and in

the same direction. Be careful not to

damage crankshaft rod journal while

installing piston.

1. Apply clean engine oil on piston,s connecting rod

bearing surface, and cylinder bore.

2. Turn crankshaft until rod journal is at bottom of its

stroke.

3. Install piston with notch (A) or oil hole (B) toward

camshaft using a ring compressor. Push piston down

until connecting rod is seated on crankshaft rod journal.

M36363 -UN-29JAN90M36364 -UN-29JAN90M36407 -UN-29JAN90

M98,2030K,38 -19-10OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-23 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Connecting rod caps must be installed

on the same connecting rod they were

removed from and in the same

direction.

4. Apply clean engine oil on connecting rod cap.

5. Install connecting rod cap with this side (A) outward

on connecting rod.

Install connecting rod cap with large tang (B) away from

camshaft on connecting rod. B43E, B43G, B48G, P218G, and P220G

T260 Engine

M36408 -UN-29JAN90M36409 -UN-29JAN90

6. Install and tighten nuts or cap screws evenly to

specifications. Hit connecting rod cap LIGHTLY with a

soft-faced hammer to align it with connecting rod.

CONNECTING ROD SPECIFICATIONS

Engine Measurement Specification

B43E, B43G, B48G, Cap Nut Torque 18 ± 1 N·m

P218G, P220G (159 ± 9 lb-in.)

T260 Cap Screw Torque 20 ± 1 N·m

(177 ± 9 lb-in.)

M36383 -UN-29JAN90M36410 -UN-29JAN90

M98,2030K,39 -19-02FEB87

M98,2030K,40 -19-02FEB87

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-24 16, 18, 20 & 24HP Onan Engines

130495

NOTE: To install cylinder head on T260 engine, go to

Step 9.

7. Install a new gasket on cylinder head.

8. Install cylinder head on cylinder block with the five

longest cap screws in the top holes of cylinder head.

Tighten cap screws in several steps in the sequence

shown.

CAP SCREW TORQUE SPECIFICATIONS

B43E, B48G, P218G, P220G Engine . . . . . . . . . . . . . . . 20 ± 1 N·m

(180 ± 12 lb-in.)

B43E Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 ± 1 N·m

(204 ± 12 lb-in.)

M36411 -UN-29JAN90M36412 -UN-29JAN90

9. Install a new gasket on cylinder head.

10. Install cylinder head on cylnder block. Install flat

washer (A), two compression washers (B) with outside

edges contacting each other, and nut (C) on each of the

top six longer studs. Install flat washer and nut on each

of the bottom four shorter studs. Tighten nuts in several

steps in sequence shown.

NUT TORQUE SPECIFICATIONS

T260 Engine

Top Six Nuts

(with compression washers) . . . . . . . . . . . . . . . . . . . . 16 ± 1 N·m

(142 ± 12 lb-in.)

Bottom Four Nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 ± 1 N·m

(180 ± 12 lb-in.)

M36413 -UN-29JAN90M36414 -UN-29JAN90

M98,2030K,41 -19-11FEB87

M98,2030K,42 -19-10OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-25 16, 18, 20 & 24HP Onan Engines

130495

11. Install a new gasket (A) on oil base.

12. Install oil base. Install and tighten four cap screws to

27 ± 3 N·m (239 ± 27 lb-in.).

M36415 -UN-29JAN90M36416 -UN-29JAN90

13. Install flywheel shroud (C) and fasten with three cap

screws.

14. Install fuel pump (B) and fasten with two screws.

15. Connect governor spring (A) in top hole of arm.

M36291 -UN-29JAN90

M98,2030K,43 -19-10OCT85

M98,2030K,44 -19-10OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-26 16, 18, 20 & 24HP Onan Engines

130495

16. Connect fuel pump impulse line (B) and fasten with

hose clamp (A).

M36290 -UN-29JAN90

17. Install right side shroud (E), lift bracket (D), and

fasten with five cap screws (C). Tighten lift bracket cap

screw to 11 ± 3 N·m (97 ± 27 lb-in.).

18. Connect spark plug wire (A) and voltage regulator

leads (B). Install the two stator leads on “AC” terminals

and the battery lead on “B+” terminal of the voltage

regulator.

A—Spark Plug Wire

B—Voltage Regulator Leads

C—Cap Screw (5 used)

D—Lift Bracket

E—Right Side Shroud

M36289 -UN-29JAN90

19. Install left side shroud (D), oil fill tube bracket (C), lift

bracket (B), and fasten with six cap screws. Tighten lift

bracket cap screw to 11 ± 3 N·m (97 ± 27 lb-in.).

20. Connect spark plug wire (A).

21. Install engine. (See machine technical manual.)

A—Spark Plug Wire

B—Lift Bracket

C—Oil Fill Tube Bracket

D—Left Side Shroud

M36472 -UN-29JAN90

M98,2030K,45 -19-10OCT85

M98,2030K,46 -19-10OCT85

M98,2030K,47 -19-10OCT85

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-27 16, 18, 20 & 24HP Onan Engines

130495

Connecting Rods and Pistons/Pistons and Connecting Rods

CTM2 (19APR90) 30-28 16, 18, 20 & 24HP Onan Engines

130495

ESSENTIAL TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Number Name Use

JDG327 Puller Legs Remove crankshaft gear and bearing plate.

JDG 329 Seal Expander Protect and install oil seal on JDG 328.

JDG 328 Crankshaft Seal Installer Install oil seal in bearing plate.

SERVICE EQUIPMENT AND TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Name Use

13-Ton Puller Set Remove crankshaft gear and bearing plate.

Bushing, Bearing, and Seal Driver Set Remove crankshaft gear, oil seal, main

bearings.

Ridge Reamer Remove ridge from top of cylinder bore.

Outside Micrometer Measure crankshaft main bearing journals.

Telescoping Gauge Measure crankshaft main bearing.

Feeler Gauge Measure crankshaft end play.

Piston Ring Compressor Install pistons.

OTHER MATERIAL

Number Name Use

T43515 John Deere LOCTITE® Retaining Apply to outside surface of main

Compound bearing

LOCTITE is a trademark of the Loctite Corp.

M98,2035K,1 -19-10OCT85

M98,2035K,2 -19-10OCT85

M98,2035K,3 -19-12NOV85

Group 35

Crankshaft and Main Bearings

CTM2 (19APR90) 35-1 16, 18, 20 & 24HP Onan Engines

130495

SERVICE PARTS KITS

The following kits are available through your parts

catalog:

Overhaul Gasket Kit

Crankshaft Bearing Kit

Oil Pump Gasket Kit

SPECIFICATIONS

Item Measurement Specification

1. Main Bearing Journal O.D. 50.78—50.80 mm 50.72 mm (1.997 in.)

(1.9992—2.0000 in.)

2. Main Bearing I.D.—B43E, B43G, 50.838—50.902 mm 50.930 mm (2.0051 in.)

B48G, T260 Engines (2.0015—2.0040 in.)

3. Main Bearing I.D. P218G, P220G 50.06—50.88 mm 50.94 mm (2.0055 in.)

Engine (2.0024—2.0034 in.)

4. Bearing Clearance —B43E, 0.064—0.097 mm 0.145 mm (0.0057 in.)

B43G, B48G, T260 Engines (0.0025—0.0038 in.)

5. Bearing Clearance—P218G, 0.061—0.106 mm 0.156 mm (0.006 in.)

P220G Engines (0.0024—0.0042 in.)

6. Bearing Plate Cap Screws Torque 35 ± 1 N·m (310 ± 9 lb-in.)

7. End Play: B43E, B43G, B48G, 0.15—0.30 mm (0.006—0.012

P218G, P220G Engines in.)

T260 Engine 0.13—0.23 mm (0.005—0.009

in.)

8. Connecting Rod Cap Nut Torque 18 ± 1 N·m (159 ± 9 lb-in.)

B43E, B43G, B48G, P218G, P220G

Engines

9. Connecting Rod Cap Screw 20 ± 1 N·m (177 ± 9 lb-in.)

Torque T260 Engine

M98,2035K,4 -19-10OCT85

M98,2035K,5 -19-02FEB87

Crankshaft and Main Bearings/Specifications

CTM2 (19APR90) 35-2 16, 18, 20 & 24HP Onan Engines

130495

REMOVE CRANKSHAFT AND MAIN

BEARINGS

1. Remove engine. (See machine technical manual.)

2. Remove muffler and exhaust pipes.

3. Remove intake manifold. (See Remove Intake

Manifold, Group 10 in this manual.)

4. Remove cylinder heads. (See Remove Cylinder

Heads, Group 10 in this manual.)

5. Remove intake and exhaust valves. (See Remove

Intake and Exhaust Valves, Group 15 in this manual.)

6. Remove flywheel. (See Remove Flywheel, Group 20

in this manual.)

7. Remove camshaft. (See Remove Camshaft, Group 25

in this manual.)

8. Remove oil pump and oil base. (See Remove Oil

Pump and Remove Oil Base, Group 40 in this manual.)

9. Remove crankshaft gear using JDG 327 Puller Legs

(A), 1 in. driver disk (B), and a puller.

IMPORTANT: If crankshaft gear is replaced, always

replace camshaft gear also.

10. Inspect crankshaft gear for chipped or broken teeth.

Replace crankshaft gear if necessary.

M36332 -UN-29JAN90

11. Remove key if necessary.

M36333 -UN-29JAN90

M98,2035K,6 -19-10OCT85

M98,2035K,7 -19-10OCT85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-3 16, 18, 20 & 24HP Onan Engines

130495

12. If necessary, remove ridge from top of cylinder bore

using a ridge reamer.

M36334 -UN-29JAN90

IMPORTANT: Connecting rod caps must be installed

in the same connecting rod they were

removed from.

13. Put identification marks on connecting rods, rod

caps, and cylinder block to aid in assembly. Remove

nuts to remove connecting rod caps.

Remove cap screws to remove connecting rod caps.

B43E, B43G, B48G, P218G and P220G

T260 Engine

M36335 -UN-29JAN90M36336 -UN-29JAN90

14. Push piston and connecting rod out of cylinder bore

using a wooden dowel.

M36337 -UN-29JAN90

M98,2035K,8 -19-10OCT85

M98,2035K,9 -19-02FEB87

M98,2035K,10 -19-10OCT85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-4 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Do not remove bearing plate using

screwdrivers. Cylinder block or bearing

plate sealing surface may be damaged.

15. Remove five cap screws to remove bearing plate

and gasket.

16. If bearing plate is tight, remove bearing plate using

JDG 327 Puller Legs (B) and a puller.

M36338 -UN-29JAN90M36339 -UN-29JAN90

17. If equipped, remove thrust washer (A) and shim (B).

IMPORTANT: Do not allow crankshaft lobes to hit

cylinder block while removing

crankshaft. Machined surfaces may be

damaged.

18. Turn crankshaft until lobe (C) fits into cylinder block

notch (D). Carefully remove crankshaft.

A—Thrust Washer

B—Shim

C—Crankshaft Lobe

D—Cylinder Block Notch

M36340 -UN-29JAN90

M98,2035K,11 -19-10OCT85

M98,2035K,12 -19-10OCT85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-5 16, 18, 20 & 24HP Onan Engines

130495

NOTE: Original rear bearing uses a separate thrust

washer. Replacement rear bearing is a one piece

assembly with the thrust washer part of the

bearing.

19. If equipped, remove thrust washer and shim.

M36341 -UN-29JAN90

INSPECT CRANKSHAFT AND MAIN

BEARINGS

1. Measure crankshaft main bearing journal outside

diameter.

NOTE: If engine has had previous major overhaul,

crankshaft journals may have been ground and

undersize bearings installed.

2. Measure several places around each journal and each

side of both journals.

NOTE: For connecting rod journal specifications, see

Piston and Connecting Rods in Group 30 in this

section.

MAIN BEARING JOURNAL SPECIFICATIONS

Item New Parts Wear Tolerance

Journal O.D. 50.78—50.80 mm 50.72 mm

(1.9992—2.0000 in.) (1.997 in.)

If journal diameter is less than 50.72 mm (1.997 in.),

replace crankshaft or have journals ground by a qualified

machine shop. The following undersize main bearings

are available:

0.05 mm (0.002 in.)

0.25 mm (0.010 in.)

0.50 mm (0.020 in.)

0.76 mm (0.030 in.)

M36342 -UN-29JAN90

M98,2035K,13 -19-10OCT85

M98,2035K,14 -19-12NOV85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-6 16, 18, 20 & 24HP Onan Engines

130495

3. Measure main bearing diameter and main bearing

clearance (bearing I.D. minus journal O.D.).

MAIN BEARING SPECIFICATIONS

Item New Part Wear Tolerance

Bearing I.D.

B43E,B43G,B48G, 50.838—50.902 mm 50.930 mm

T260 Engines (2.0015—2.0040 in.) (2.0051 in.)

Bearing Clearance

B43E,B43G,B48G, 0.064—0.097 mm 0.145 mm

T260 Engines (0.0025—0.0038 in.) (0.0057 in.)

Bearing I.D.—

P218G and P220G 50.06—50.88 mm 50.94 mm

Engine (2.0024—2.0034 in.) (2.0055 in.)

Bearing Clearance

P218G and P220G 0.061—0.106 mm 0.156 mm

Engine (0.0024—l0.0042 in.) (0.006 in.)

If bearing diameter exceeds 50.930 mm (2.0051 in.),

replace bearing.

If bearing clearance exceeds 0.145 mm (0.0057 in.),

replace bearing or grind crankshaft journals. Install

undersize bearings.

If bearing diameter and clearance are within

specifications and bearings are not damaged, bearings

can be reused.

M36343 -UN-29JAN90M36344 -UN-29JAN90

4. Remove oil seal (A) using a 2 in. driver disk.

M36345 -UN-29JAN90

M98,2035K,15 -19-12FEB87

M98,2035K,16 -19-10OCT85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-7 16, 18, 20 & 24HP Onan Engines

130495

5. Carefully remove crankshaft bearing (A) using a 2 in.

driver disk (B) and 2-1/8 in. disk (C).

M36346 -UN-29JAN90

IMPORTANT: Support cylinder block to avoid

distortion and damage to bearing bore

during removal.

6. Carefully remove crankshaft bearing (A) using 2 in.

driver disk (B), 2-1/8 in. driver disk (C), and a pipe (D).

A—Crankshaft Bearing

B—2 in. Driver Disk

C—2-1/8 in. Driver Disk

D—Pipe

M36347 -UN-29JAN90

7. Clean and inspect oil passages in main bearing

journals, connecting rod journals, main bearing bore in

cylinder block, and main bearing bore in bearing plate.

M36348 -UN-29JAN90

8. Inspect lock pins (A) in bearing plate and cylinder

block for wear or damage. If necessary, remove lock

pins using an Easy-Out tool.

M36349 -UN-29JAN90

M98,2035K,17 -19-10OCT85

M98,2035K,18 -19-10OCT85

M98,2035K,19 -19-10OCT85

M98,2035K,20 -19-10OCT85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-8 16, 18, 20 & 24HP Onan Engines

130495

INSTALL CRANKSHAFT AND MAIN

BEARINGS

1. Clean and dry all parts. Apply clean engine oil on all

internal parts before assembly.

2. If necessary, install new lock pins (A) in bearing plate

and cylinder block.

M36349 -UN-29JAN90

3. Clean bearing O.D. and bearing bore in cylinder block

with primer.

4. Apply retaining compound supplies with bearing on

bearing O.D. and bearing bore in cylinder block.

NOTE: Replacement bearing has a flange which is used

as the thrust washer.

5. Align oil holes (A) in bearing with oil holes (B) in

cylinder block. Align notches (C) in bearing with lock pins

(D) in cylinder block.

6. Install bearing using a 2 in. driver disk and 2-3/8 in.

disk. Push bearing tight against cylinder block. Be sure

bearing notch is around lock pin. Remove excess

retaining compound from bearing I.D. and flange.

A—Bearing Oil Holes

B—Cylinder Block Oil Holes

C—Bearing Notches

D—Lock Pins

M36350 -UN-29JAN90M36351 -UN-29JAN90

NOTE: Bearing can be put in a freezer to aid installation.

7. Apply clean engine oil on outside surface of bearing.

8. Align oil hole (A) in bearing with oil hole (B) in bearing

plate. Install bearing using a 2 in. driver disk and 2-3/8

in. disk. Push bearing flush with surface of bearing plate.

M36352 -UN-29JAN90

M98,2035K,21 -19-10OCT85

M98,2035K,22 -19-10OCT85

M98,2035K,23 -19-10OCT85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-9 16, 18, 20 & 24HP Onan Engines

130495

9. Apply multipurpose grease between lips of oil seal.

M36353 -UN-29JAN90

10. Install JDG 329 Seal Expander (A) in JDG 328

Crankshaft Seal Installer (B).

11. Install oil seal with lips toward crankshaft seal

installer. Push oil seal tight against shoulder of

crankshaft seal installer. Remove seal expander ONLY.

M36354 -UN-29JAN90

12. Remove old seal material from oil seal bore in

bearing plate.

13. Install oil seal (A) using JDG 328 Crankshaft Seal

Installer (B) and 2-3/16 in. driver disk (C). Push oil seal

to bottom of bearing plate bore. DO NOT remove

crankshaft seal installer at this time.

M36355 -UN-29JAN90

M98,2035K,24 -19-10OCT85

M98,2035K,25 -19-10OCT85

M98,2035K,26 -19-10OCT85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-10 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Original rear bearing uses a separate

thrust washer. Replacement rear

bearing is a one piece assembly with

the thrust washer part of the bearing.

Do not install thrust washer or shim

when replacement bearing is used.

14. Apply multipurpose grease on plain side of thrust

washer.

15. Install thrust washer with oil grooves (A) toward

crankshaft and notches (B) between lock pins (C). DO

NOT install shim on this side of crankshaft.

M36356 -UN-29JAN90

16. Apply clean engine oil on main bearings and

crankshaft main bearing journals.

IMPORTANT: Do not allow crankshaft lobes to hit

cylinder block while installing

crankshaft. Machined surfaces may be

damaged.

17. Turn crankshaft until lobe (A) fits into cylinder block

notch (B). Carefully install crankshaft.

M36357 -UN-29JAN90

18. Align notch (A) in new gasket with notch (B) in

bearing plate and install gasket.

19. Apply multipurpose grease on plain side of washer.

20. Install thrust washer with oil grooves (C) toward

crankshaft and notches (D) between lock pins (E). DO

NOT install shim at this time.

A—Gasket Notch

B—Bearing Plate Notch

C—Oil Grooves

D—Thrust Washer Notches

E—Lock Pins

M36358 -UN-29JAN90

M98,2035K,27 -19-12NOV85

M98,2035K,28 -19-10OCT85

M98,2035K,29 -19-12NOV85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-11 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Bearing plate will fit tight against

cylinder block only if lock pins are in

thrust washer notches. Do not pull

bearing plate inward using cap screws

as lock pins, thrust washer or

crankshaft may be damaged.

21. Align notch (A) in bearing plate with plug (B).

Carefully install bearing plate. If bearing plate will not fit

tight against cylinder block, remove bearing plate and

check thrust washer position. Remove JDG 328

Crankshaft Seal Installer (C).

22. Install and tighten five cap screws to 35 ± 1 N·m

(310 ± 9 lb-in.).

M36359 -UN-29JAN90M36360 -UN-29JAN90

23. Measure crankshaft end play using a feeler gauge.

CRANKSHAFT SPECIFICATIONS

Engine Measurement Specification

B43E, B43G, B48G, End Play 0.15—0.30 mm

P218G, P220G (0.006—0.012 in.)

T260 End Play 0.13—0.23 mm

(0.005—l0.009 in.)

If end play exceeds specifications, remove bearing plate

and add shim(s).

M36361 -UN-29JAN90

M98,2035K,30 -19-10OCT85

M98,2035K,31 -19-11FEB87

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-12 16, 18, 20 & 24HP Onan Engines

130495

24. Install shim or shims between bearing plate and

thrust washer. Be sure shim and thrust washer notches

(A) are between lock pins (B). Repeat steps 21—23.

NOTE: Shims are available in 0.13 mm (0.005 in.)

thickness only. Use shims as required.

M36362 -UN-29JAN90

IMPORTANT: Pistons must be installed in the same

cylinder they were removed from and in

the same direction.

25. Apply clean engine oil on pistons, connecting rod

bearing, and cylinder bore.

26. Turn crankshaft until rod bearing journal is at bottom

of its stroke.

IMPORTANT: Be careful not to damage crankshaft

rod journal while installing piston.

27. Install pistons with notch (A) or oil hole (B) toward

camshaft using a ring compressor and wooden dowel.

Push piston down until connecting rod is seated on

crankshaft rod journal.

M36363 -UN-29JAN90M36364 -UN-29JAN90M36365 -UN-29JAN90

M98,2035K,32 -19-10OCT85

M98,2035K,33 -19-10OCT85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-13 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Connecting rod caps must be installed

on the same connecting rod they were

removed from and in the same

direction.

28. Apply clean engine oil on connecting rod cap.

29. Install connecting rod cap with this side (A) outward

on connecting rod.

Install connecting rod cap with large tang (B) away from

camshaft on connecting rod. B43E, B43G, B48G, P218G, and P220G

T260 Engine Shown

M36366 -UN-29JAN90M36367 -UN-29JAN90

30. Install and tighten nuts or cap screws evenly to

specifications. Hit connecting rod cap LIGHTLY with a

soft-faced hammer to align it with connecting rod.

CONNECTING ROD SPECIFICATIONS

Engine Measurement Specification

B43E, B43G, B48G, Cap Nut Torque 18 ± 1 N·m

P218G, P220G (159 ± 9 lb-in.)

T260 Cap Screw Torque 20 ± 1 N·m

(177 ± 9 lb-in.)

M36368 -UN-29JAN90M36369 -UN-29JAN90

M98,2035K,34 -19-02FEB87

M98,2035K,35 -19-02FEB87

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-14 16, 18, 20 & 24HP Onan Engines

130495

31. Install key if removed.

M36370 -UN-29JAN90

32. Install crankshaft gear using the following heat

method or by driver method. The heat method is

recommended.

NOTE: For driver method, go to Step 33.

HEAT METHOD

a. Heat crankshaft gear to 232˚ C (450˚F) for 1/2 hour

using a bearing oven.

NCAUTION: Gear is hot. Be careful not to burn

hands while installing gear.

b. Align slot (A) in gear with key (B) in crankshaft.

c. Install gear with holes (C) outward on crankshaft.

Push gear tight against crankshaft shoulder.

M36371 -UN-29JAN90

M98,2035K,36 -19-10OCT85

M98,2035K,37 -19-12NOV85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-15 16, 18, 20 & 24HP Onan Engines

130495

33. Install crankshaft gear using the following driver

method.

DRIVER METHOD

a. Align slot (A) in gear with key (B) in crankshaft.

IMPORTANT: Support engine on crankshaft only. Do

not support engine on cylinder block.

Block may be damaged.

b. Install gear with holes (C) outward on crankshaft using

a 1-5/8 in. I.D. pipe (D), 1-9/16 in. driver disk (E), and

1-15/16 in. driver disk (F). Push gear tight against

crankshaft shoulder.

A—Slot

B—Key

C—Holes

D—1-5/8 in. I.D. Pipe

E—1-9/16 in. Driver Disk

F—1-15/16 in. Driver Disk

M36372 -UN-29JAN90M36373 -UN-29JAN90

34. Install oil pump and oil base. (See Install Oil Pump

and Install Oil Base, Group 40 in this manual.)

35. Install camshaft. (See Install Camshaft, Group 25 in

this manual.)

36. Install flywheel. (See Install Flywheel, Group 20 in

this manual.)

37. Install intake and exhaust valves. (See Install Intake

and Exhaust Valves, Group 15 in this manual.)

38. Install cylinder heads. (See Install Cylinder Heads,

Group 10 in this manual.)

39. Install intake manifold. (See Install Intake manifold,

Group 10 in this manual.)

40. Install muffler and exhaust pipes. (See Install Intake

Manifold, Group 10 in this manual.)

41. Install engine. (See machine technical manual.)

M98,2035K,37A -19-12NOV85

M98,2035K,38 -19-12NOV85

Crankshaft and Main Bearings/Crankshaft and Main Bearings

CTM2 (19APR90) 35-16 16, 18, 20 & 24HP Onan Engines

130495

ESSENTIAL TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Number Name Use

JDG 325 Crankshaft Seal Installer Install gear cover oil seal.

JDG 333 Crowsfoot Wrench Tighten oil filter adapter cap screws.

SERVICE EQUIPMENT AND TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Name Use

Bushing, Bearing, and Seal Driver Set Remove gear cover oil seal.

Dial Indicator Measure oil pump gear backlash and starter

pinion gear backlash.

13-Ton Puller Set Remove flywheel

OTHER MATERIAL

Number Name Use

TY 9375 John Deere LOCTITE® Pipe Apply to threads of gear cover,

Sealant with TEFLON®flywheel, and oil filter adapter cap

screws.

LOCTITE is a trademark of the Loctite Corp.

TEFLON is a trademark of the DuPont Co.

M98,2040K,1 -19-11NOV85

M98,2040K,2 -19-11NOV85

M98,2040K,3 -19-11OCT85

Group 40

Lubrication System

CTM2 (19APR90) 40-1 16, 18, 20 & 24HP Onan Engines

130495

SERVICE PARTS KITS

The following kits are available through your parts

catalog:

Oil Pump Gasket Kit

Overhaul Gasket Kit

M98,2040K,4 -19-11OCT85

Lubrication System/Service Parts Kits

CTM2 (19APR90) 40-2 16, 18, 20 & 24HP Onan Engines

130495

SPECIFICATIONS

Oil Pump

Item New Specification Wear Tolerance

1. Gear Backlash: B43E, 0.05—0.13 mm 0.23 mm (0.009 in.)

B43G, B48G, T260 Engines (0.002—0.005 in.)

Gear Backlash: P218G, 0.025—0.203 mm 0.36 mm

P220G Engines (0.001—0.008 in.) (0.014 in.)

2. Gear Housing Cap Screw

Torque: B43E, B43G, 19 ± 2 N·m

B48G, T260 Engines (168 ± 18 lb-in.)

Gear Housing Cap Screw

Torque: P218G, P220G 10 N·m

Engines (88 lb-in.)

3. Oil Pump-to-Cylinder 11 ± 1 N·m

Block Cap Screw Torque (97 ± 9 lb-in.)

4. Gear Cover Cap Screw 12 ± 1 N·m

Torque (106 ± 9 lb-in.)

Oil Pressure Regulating Valve

1. Spring Free Length (approx) 25 mm (1.0 in.)

Spring Test Length 13 mm (0.5 in.) at 12 N (2.6 lb force )

2. Oil Pressure Regulating 28 ± 3 N·m

Valve Cap Screw Torque (248 ± 27 lb-in.)

Oil Base

1. Starter-to-Oil Base 34 ± 1 N·m

Cap Screw Torque (301 ± 9 lb-in.)

2. Oil Base-to-Oil Base 27 ± 3 N·m

Block Cap Screw Torque (239 ± 27 lb-in.)

3. Starter Pinion Gear 318 S.N. ( —231,857) 0.51 ± 0.38 mm

Backlash (Adjustable 420 S.N. ( —224, 882) (0.020 ± 0.015 in.)

Starter Bracket Only)

4. B43E, B43G, B48G, T260

Engine: Flywheel Cap Screw 51 ± 3 N·m

Torque (38 ± 2 lb-ft)

5. Lift Bracket Cap Screw 11 ± 3 N·m

Torque (97 ± 27 lb-in.)

Oil Filter Adapter

Item Measurement Specification

1. Attaching Cap Screw Torque 12 ± 1 N·m (106 ± 9 lb-in.)

2. Lift Bracket Cap Screw Torque 11 ± 3 N·m (97 ± 27 lb-in.)

3. Oil Filter Bypass Valve Torque 28 ± 3 N·m (248 ± 27 lb-in.)

Cap Screw (910 and 930

Front Mowers)

M98,2040K,5 -19-11FEB87

Lubrication System/Specifications

CTM2 (19APR90) 40-3 16, 18, 20 & 24HP Onan Engines

130495

REMOVE OIL PUMP

1. Remove engine. (See machine technical manual.)

2. Remove flywheel. (See Group 20 in this manual.)

3. Remove clip (A) to disconnect governor rod (B) from

governor arm (C).

M36417 -UN-29JAN90

IMPORTANT: Do not hit gear cover with a metal

hammer or remove cover with a

screwdriver. Doing so can damage gear

cover.

4. Remove four cap screws and nut to remove clip (A),

gear cover, and gasket (B).

If gear cover is tight, LIGHTLY hit gear cover with a

soft-hammer to loosen it.

M36418 -UN-29JAN90

5. Remove oil seal using a 2 in. driver disk.

M36302 -UN-29JAN90

M98,2040K,7 -19-11OCT85

M98,2040K,8 -19-11OCT85

M98,2040K,9 -19-11OCT85

Lubrication System/Oil Pump

CTM2 (19APR90) 40-4 16, 18, 20 & 24HP Onan Engines

130495

6. Measure oil pump gear backlash.

OIL PUMP GEAR SPECIFICATIONS

Item New Part Wear Tolerance

Backlash—B43E,

B43G, B48G, 0.05—0.13 mm 0.23 mm

T260 Engine (0.002—0.005 in.) (0.009 in.)

Backlash—P218G, 0.025—0.203 mm 0.36 mm

P220G Engine (0.001—0.008 in.) (0.014 in.)

If backlash exceeds specification replace oil pump.

M36419 -UN-29JAN90

7. Remove two cap screws to remove oil pump

assembly. If suction tube hits crankshaft lobe, install

flywheel cap screw in crankshaft. Turn crankshaft until

suction tube can be removed.

M36420 -UN-29JAN90M36421 -UN-29JAN90

M98,2040K,10 -19-02FEB87

M98,2040K,11 -19-11OCT85

Lubrication System/Oil Pump

CTM2 (19APR90) 40-5 16, 18, 20 & 24HP Onan Engines

130495

DISASSEMBLE AND INSPECT OIL PUMP

1. Inspect oil pump gear (A) for chipped or broken teeth.

If gear is damaged, replace oil pump assembly.

2. Inspect suction tube (B) for cracks, plugged suction

screen, or damage. If necessary, remove suction tube

using locking pliers.

M36422 -UN-29JAN90

3. Remove two cap screws to remove oil pump housing

and gasket (A).

4. Measure original gasket thickness. New gasket must

be the same thickness as original gasket.

M36423 -UN-29JAN90

5. Inspect gears (A) for chipped or broken teeth, scoring,

and wear.

6. Inspect housing (B) for cracks, wear or damage. If

gears or housing are damaged, replace oil pump

assembly.

M36424 -UN-29JAN90

M98,2040K,12 -19-11OCT85

M98,2040K,13 -19-11OCT85

M98,2040K,14 -19-11OCT85

Lubrication System/Oil Pump

CTM2 (19APR90) 40-6 16, 18, 20 & 24HP Onan Engines

130495

ASSEMBLE OIL PUMP

1. Thoroughly clean and dry parts. Put clean engine oil

on all internal parts.

2. Install suction tube (A), if removed, using locking

pliers.

3. Install a new gasket (B), the same thickness as

original gasket, on housing.

4. Install housing and two cap screws.

For B43E, B43G, B48G, and T260 Engines: tighten cap

screws to 19 ± 2 N·m (168 ± 18 lb-in.).

For P218G and P220G Engines: tighten cap screws to

10 N·m (88 lb-in.).

5. Fill oil pump housing with clean engine oil through

pump outlet port (C).

M36425 -UN-29JAN90M36426 -UN-29JAN90

INSTALL OIL PUMP

1. Turn crankshaft until suction tube does not hit

crankshaft lobe.

2. Install oil pump assembly. Install and tighten two cap

screws to 11 ± 1 N·m (97 ± 9 lb-in.).

M36421 -UN-29JAN90M36427 -UN-29JAN90

M98,2040K,15 -19-11FEB87

M98,2040K,16 -19-11OCT85

Lubrication System/Oil Pump

CTM2 (19APR90) 40-7 16, 18, 20 & 24HP Onan Engines

130495

3. Install oil seal (A), with lip of seal downward, in gear

cover suing JDG 325 Crankshaft Seal Installer (B).

M36325 -UN-29JAN90

4. Turn cup until the plastic bushing (A) is in the 3

o’clock position.

5. Apply multipurpose grease between cup and camshaft

gear to hold cup in position.

M36428 -UN-29JAN90

M98,2040K,17 -19-11OCT85

M98,2040K,18 -19-11OCT85

Lubrication System/Oil Pump

CTM2 (19APR90) 40-8 16, 18, 20 & 24HP Onan Engines

130495

6. Install new gasket on cylinder block.

7. Be sure plastic bushing (A) and pin (B) are aligned.

IMPORTANT: Do not hit gear cover with a metal

hammer during installation. Gear cover

can be damaged.

8. Hold governor arm away from camshaft and carefully

install gear cover.

M36429 -UN-29JAN90M36430 -UN-29JAN90

9. Tip engine forward and move governor arm back and

forth. Governor cup should be felt moving in and out. If

no movement is felt, the pin is not in plastic bushing.

Remove gear cover and repeat Steps 7—9.

M36431 -UN-29JAN90

M98,2040K,19 -19-11OCT85

M98,2040K,20 -19-11OCT85

Lubrication System/Oil Pump

CTM2 (19APR90) 40-9 16, 18, 20 & 24HP Onan Engines

130495

10. Apply pipe sealant on cap screw (A) threads.

11. Install clip (B), four cap screws, and nut. Tighten cap

screws and nut to 12 ± 1 N·m (106 ± 9 lb-in.).

12. Install stator wiring (C) in clip.

M36432 -UN-29JAN90

13. Install clip (A) on governor arm (B). Push governor

rod (C) and governor arm toward carburetor until they

bottom out.

14. Install governor rod in closest governor arm hole. If

governor rod is between two holes, install governor rod

in next hole toward flywheel. Push clip on governor rod.

15. Install flywheel. (See Group 20 in this manual.)

16. Install engine. (See machine technical manual.)

M36433 -UN-29JAN90

REMOVE OIL PRESSURE REGULATING

VALVE

1. Park tractor safely.

2. Disconnect negative (-) battery cable.

NOTE: For T260 engine, go to Step 8.

3. Remove wing nut to remove air cleaner cover.

M36217 -UN-22NOV89

M98,2040K,21 -19-11OCT85

M98,2040K,22 -19-11OCT85

M98,2040K,23 -19-11OCT85

Lubrication System/Oil Pressure Regulating Valve

CTM2 (19APR90) 40-10 16, 18, 20 & 24HP Onan Engines

130495

4. Remove lock nut to remove plate and element (A).

M36447 -UN-29JAN90

5. Remove three cap screws to remove splash plate.

6. Remove two cap screws (A) to remove air cleaner

base (B). Pull breather hose (C) out of air cleaner base.

M36448 -UN-29JAN90

7. Loosen nut to remove air cleaner bracket.

M36449 -UN-29JAN90

8. Remove cap screw and washer (A).

M36450 -UN-29JAN90

M98,2040K,24 -19-14OCT85

M98,2040K,25 -19-14OCT85

M98,2040K,26 -19-14OCT85

M98,2040K,27 -19-14OCT85

Lubrication System/Oil Pressure Regulating Valve

CTM2 (19APR90) 40-11 16, 18, 20 & 24HP Onan Engines

130495

9. Remove spring (A) and valve (B).

10. Inspect spring, valve, and valve bore for wear or

damage.

11. Check spring using a spring compression tester.

SPRING SPECIFICATIONS

Free length (approx.) . . . . . . . . . . . . . . . . . . . . . . . 25 mm (1.0 in.)

Test length at 12 N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 mm

(2.6 lb force . . . . . . . . . . . . . . 0.5 in.)

M36451 -UN-29JAN90

INSTALL OIL PRESSURE REGULATING

VALVE

1. Thoroughly clean and dry parts.

2. Put clean engine oil on all internal parts.

3. Install valve (B) and spring (A).

M36451 -UN-29JAN90

4. Install washer (A) and cap screw. Tighten cap screw

to 28 ± 3 N·m (248 ± 27 lb-in.).

NOTE: For T260 engine, stop here.

M36452 -UN-29JAN90

5. Install air cleaner bracket. Be sure air cleaner bracket

is level and tighten nut.

M36449 -UN-29JAN90

M98,2040K,28 -19-26NOV85

M98,2040K,29 -19-14OCT85

M98,2040K,30 -19-14OCT85

M98,2040K,31 -19-14OCT85

Lubrication System/Oil Pressure Regulating Valve

CTM2 (19APR90) 40-12 16, 18, 20 & 24HP Onan Engines

130495

6. Install breather hose (C) in air cleaner base (B).

7. Install air cleaner base on carburetor. Install air intake

hose in flywheel shroud hole.

8. Install and tighten two air cleaner base cap screws

(A).

9. Install splash plate and fasten with three cap screws.

M36448 -UN-29JAN90

10. Install element (A) and plate. Install and tighten lock

nut.

M36447 -UN-29JAN90

11. Install air cleaner cover and tighten wing nut.

12. Connect negative (-) battery cable.

M36217 -UN-22NOV89

M98,2040K,32 -19-14OCT85

M98,2040K,33 -19-14OCT85

M98,2040K,34 -19-14OCT85

Lubrication System/Oil Pressure Regulating Valve

CTM2 (19APR90) 40-13 16, 18, 20 & 24HP Onan Engines

130495

REMOVE AND INSPECT OIL BASE

1. Remove engine. (See machine technical manual.)

2. Disconnect spark plug wire (A) and voltage regulator

leads (B).

3. Remove five cap screws (C) to remove lift bracket (D)

and right side shroud (E).

A—Spark Plug Wire

B—Voltage Regulator Leads

C—Cap Screw (5 used)

D—Lift Bracket

E—Right Side Shroud

M36289 -UN-29JAN90

4. Loosen hose clamp (A) to disconnect fuel pump

impulse line (B).

M36290 -UN-29JAN90

M98,2040K,35 -19-14OCT85

M98,2040K,36 -19-14OCT85

Lubrication System/Oil Base

CTM2 (19APR90) 40-14 16, 18, 20 & 24HP Onan Engines

130495

5. Disconnect governor spring (A).

6. Remove two screws to remove fuel pump (B).

7. Remove five cap screws to remove flywheel shroud

(C).

M36291 -UN-29JAN90

8. Remove screw to disconnect oil fill tube bracket.

M36434 -UN-29JAN90

9. Remove four cap screws to remove oil base and

gasket (A).

M36374 -UN-29JAN90

M98,2040K,37 -19-14OCT85

M98,2040K,38 -19-14OCT85

M98,2040K,39 -19-14OCT85

Lubrication System/Oil Base

CTM2 (19APR90) 40-15 16, 18, 20 & 24HP Onan Engines

130495

NOTE: On P218G and P220G Engines the starter is not

attached to the oil base.

10. Remove two cap screws to remove starter.

11. Inspect oil base for cracks, broken fins, or damage;

replace if necessary.

M36435 -UN-29JAN90

INSTALL OIL BASE

NOTE: On P218G and P22G Engines the starter is not

attached to the oil base.

1. Install starter and two cap screws. Tighten cap screws

to 34 ± 1 N·m (301 ± 9 lb-in.)

M36436 -UN-29JAN90

2. Install a new gasket (A) on oil base.

3. Install oil base. Install and tighten four cap screws to

27 ± 3 N·m (320 ± 27 lb-in.).

M36415 -UN-29JAN90M36416 -UN-29JAN90

M98,2040K,40 -19-02FEB87

M98,2040K,41 -19-02FEB87

M98,2040K,42 -19-26NOV85

Lubrication System/Oil Base

CTM2 (19APR90) 40-16 16, 18, 20 & 24HP Onan Engines

130495

4. Install oil fill tube bracket and fasten with screw.

M36434 -UN-29JAN90

NOTE: For engines with adjustable starter bracket,

measure starter pinion gear backlash using the

following procedure. For all other units with

non-adjustable starter bracket, go to Step 18.

5. Pull starter pinion gear outward until teeth contact

flywheel ring gear. Measure starter pinion gear backlash.

Backlash specification is 0.51 ± 0.38 mm (0.020 ± 0.015

in.).

6. If backlash is not correct, loosen starter cap screws

(A) and move starter bracket (B) to obtain correct

backlash.

Tighten starter cap screws to hold bracket in position.

Check backlash again.

M36437 -UN-29JAN90M36438 -UN-29JAN90

M98,2040K,43 -19-14OCT85

M98,2040K,44 -19-14OCT85

Lubrication System/Oil Base

CTM2 (19APR90) 40-17 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Do not hold flywheel from turning with

a pry bar. Doing so can damage fins.

7. Fasten locking pliers to ring gear to prevent flywheel

from turning.

NCAUTION: Loosen flywheel cap screw only two

turns. Do not remove cap screw. If cap screw

is removed, flywheel may cause injury when it

comes loose.

8. Loosen cap screw two turns only.

M36292 -UN-29JAN90

IMPORTANT: Do not pry on flywheel with a

screwdriver. Ceramic magnets or gear

case cover can be damaged.

9. Loosen flywheel using a puller.

10. Remove puller, cap screw, washer, and flywheel.

M36293 -UN-29JAN90

11. Tighten starter cap screws to 34 ± 1 N·m (301 ± 9

lb-in.).

M36439 -UN-29JAN90

M98,2040K,45 -19-21OCT85

M98,2040K,46 -19-21OCT85

M98,2040K,47 -19-21OCT85

Lubrication System/Oil Base

CTM2 (19APR90) 40-18 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Do not lubricate crankshaft taper. The

crankshaft taper must able dry to hold

the flywheel tight.

12. Clean crankshaft taper before installing flywheel.

13. Apply pipe sealant on threads of flywheel cap screw.

14. Align keyway (A) in flywheel with key (B) in

crankshaft. Install flywheel.

15. Install washer and cap screw.

16. Fasten locking pliers to ring gear to prevent flywheel

from turning.

17. On B43E, B43G, B48G, T260 Engines: tighten cap

screw to 51 ± 3 N·m (38 ± 2 lb-ft).

M36297 -UN-29JAN90M36298 -UN-29JAN90

18. Install flywheel shroud (C) and fasten with five cap

screws.

19. Install fuel pump (B) and fasten with two screws.

20. Connect governor spring (A) in top hole of arm.

M36291 -UN-29JAN90

M98,2040K,48 -19-11FEB87

M98,2040K,49 -19-21OCT85

Lubrication System/Oil Base

CTM2 (19APR90) 40-19 16, 18, 20 & 24HP Onan Engines

130495

21. Connect fuel pump impulse line (B) and fasten with

hose clamp (A).

M36290 -UN-29JAN90

22. Install right side shroud (E), lift bracket (D), and

fasten with five cap screws (C). Tighten lift bracket cap

screw to 11 ± 3 N·m (97 ± 27 lb-in.).

23. Connect spark plug wire (A) and voltage regulator

leads (B). Install the two stator leads on “AC” terminals

and the battery lead on “B+” terminal of the voltage

regulator.

24. Install engine. (See machine technical manual.)

A—Spark Plug Wire

B—Voltage Regulator Leads

C—Cap Screw (5 used)

D—Lift Bracket

E—Right Side Shroud

M36289 -UN-29JAN90

M98,2040K,50 -19-21OCT85

M98,2040K,51 -19-21OCT85

Lubrication System/Oil Base

CTM2 (19APR90) 40-20 16, 18, 20 & 24HP Onan Engines

130495

REMOVE OIL FILTER ADAPTER

1. Remove engine. (See machine technical manual.)

2. Disconnect spark plug wire (A) and voltage regulator

leads (B).

3. Remove five cap screws (C) to remove lift bracket

(D), and right side shroud (E).

A—Spark Plug Wire

B—Voltage Regulator Leads

C—Cap Screw (5 used)

D—Lift Bracket

E—Right Side Shroud

M36289 -UN-29JAN90

4. Remove oil filter (A).

5. Disconnect engine oil pressure sender wiring lead (B).

M36440 -UN-29JAN90

6. Remove two cap screws to remove oil filter adapter

and gasket (A).

M36441 -UN-29JAN90

M98,2040K,52 -19-21OCT85

M98,2040K,53 -19-21OCT85

M98,2040K,54 -19-21OCT85

Lubrication System/Oil Filter Adapter

CTM2 (19APR90) 40-21 16, 18, 20 & 24HP Onan Engines

130495

7. Remove two cap screws to remove drain pan.

8. Remove engine oil pressure sender (A).

9. Inspect oil filter adapter for thread damage, cracks or

damage; replace as necessary.

M36442 -UN-29JAN90

INSTALL OIL FILTER ADAPTER

1. Install engine oil pressure sender (A).

2. Install drain pan and fasten with two cap screws.

M36442 -UN-29JAN90

3. Install new gasket (A) on oil filter adapter.

4. Apply pipe sealant on top cap screw threads.

5. Install oil filter adapter and two cap screws. Tighten

cap screws to 12 ± 1 N·m (106 ± 9 lb-in.) using JDG

333 Crowsfoot Wrench (B) or a 1/2 in crowsfoot wrench.

M36443 -UN-29JAN90M36444 -UN-29JAN90

M98,2040K,55 -19-21OCT85

M98,2040K,56 -19-21OCT85

M98,2040K,57 -19-21OCT85

Lubrication System/Oil Filter Adapter

CTM2 (19APR90) 40-22 16, 18, 20 & 24HP Onan Engines

130495

6. Connect engine oil pressure sender wiring lead (B).

7. Install oil filter (A).

M36440 -UN-29JAN90

8. Install right side shroud (E), lift bracket (D), and fasten

with five cap screws (C). Tighten lift bracket cap screw

to 11 ± 3 N·m (97 ± 26 lb-in.).

9. Connect spark plug wire (A) and voltage regulator

leads (B). Install the two stator leads on “AC” terminals

and the battery lead on “B+” terminal of the voltage

regulator.

10. Install engine. (See machine technical manual.)

A—Spark Plug Wire

B—Voltage Regulator Leads

C—Cap Screw (5 used)

D—Lift Bracket

E—Right Side Shroud

M36289 -UN-29JAN90

M98,2040K,58 -19-21OCT85

M98,2040K,59 -19-21OCT85

Lubrication System/Oil Filter Adapter

CTM2 (19APR90) 40-23 16, 18, 20 & 24HP Onan Engines

130495

REMOVE OIL LINE ADAPTER

1. Remove engine. (See machine technical manual.)

2. Remove three cap screws to remove lift bracket (A)

and exhaust shroud (B).

3. Remove four cap screws to remove left side shroud

(C).

M36445 -UN-29JAN90

4. Disconnect engine oil pressure sender wiring lead (A).

M36446 -UN-29JAN90

5. Remove two special screw to remove oil adapter and

gasket (A).

M36453 -UN-29JAN90

M98,2040K,60 -19-21OCT85

M98,2040K,61 -19-21OCT85

M98,2040K,62 -19-21OCT85

Lubrication System/Oil Line Adapter

CTM2 (19APR90) 40-24 16, 18, 20 & 24HP Onan Engines

130495

6. Remove oil adapter hoses.

7. Remove engine oil pressure sender (A) and elbow

(B).

M36454 -UN-29JAN90

8. Remove cap screw (A), washer (B), spring (C), and

valve (D).

9. Inspect spring, valve, and valve bore for wear or

damage.

A—Cap Screw

B—Washer

C—Spring

D—Valve

M36455 -UN-29JAN90

INSTALL OIL LINE ADAPTER

1. Thoroughly clean and dry parts.

2. Put clean engine oil on all internal parts.

3. Install valve(D), spring (C), washer (B), and cap screw

(A). Tighten cap screw to 28 ± 3 N·m (248 ± 27 lb-in.).

A—Cap Screw

B—Washer

C—Spring

D—Valve

M36455 -UN-29JAN90

M98,2040K,63 -19-21OCT85

M98,2040K,64 -19-21OCT85

M98,2040K,65 -19-21OCT85

Lubrication System/Oil Line Adapter

CTM2 (19APR90) 40-25 16, 18, 20 & 24HP Onan Engines

130495

4. Apply pipe sealant on threads of elbow, engine oil

pressure sender and oil adapter hoses.

5. Install elbow (B) and engine oil pressure sender (A).

6. Install oil adapter hoses.

M36454 -UN-29JAN90

7. Install new gasket on oil adapter.

8. Apply pipe sealant on top special screw threads.

9. Install oil adapter and two special screws. Tighten

special screws to 12 ± 1 N·m (106 ± 9 lb-in.).

M36456 -UN-29JAN90M36457 -UN-29JAN90

10. Connect engine oil pressure sender wiring lead (A).

M36446 -UN-29JAN90

M98,2040K,66 -19-21OCT85

M98,2040K,67 -19-21OCT85

M98,2040K,68 -19-21OCT85

Lubrication System/Oil Line Adapter

CTM2 (19APR90) 40-26 16, 18, 20 & 24HP Onan Engines

130495

11. Install left side shroud (C) and fasten with four cap

screws.

12. Install exhaust shroud (B), lift bracket (A), and three

cap screws. Tighten lift bracket cap screw to 11 ± 3 N·m

(97 ± 27 lb-in.).

13. Install engine. (See machine technical manual.)

M36445 -UN-29JAN90

M98,2040K,69 -19-21OCT85

Lubrication System/Oil Line Adapter

CTM2 (19APR90) 40-27 16, 18, 20 & 24HP Onan Engines

130495

Lubrication System/Oil Line Adapter

CTM2 (19APR90) 40-28 16, 18, 20 & 24HP Onan Engines

130495

SERVICE EQUIPMENT AND TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Name Use

Press Remove and install camshaft gear.

Bushing, Bearing, and Seal Driver Set Remove and install gear cover bushing and oil

seal

OTHER MATERIAL

Number Name Use

T43512 John Deere LOCTITE Thread Lock Apply to threads of governor fork

and Sealer (Medium Strength) screws

LOCTITE is a trademark of the Loctite Corp.

SERVICE PARTS KITS

The following kits are available through your parts

catalog:

Overhaul Gasket Kit

SPECIFICATIONS

Item Measurement Specification

Governor Cup Travel 5.6 mm (0.22 in.)

Gear cover surface-to-pin Distance 19 mm (0.75 in.)

M98,2045K,1 -19-21OCT85

M98,2045K,2 -19-21OCT85

M98,2045K,2A -19-11NOV85

M98,2045K,3 -19-21OCT85

Group 45

Governor

CTM2 (19APR90) 45-1 16, 18, 20 & 24HP Onan Engines

130495

REMOVE GOVERNOR ASSEMBLY AND

GOVERNOR LINKAGE

1. Remove engine. (See machine technical manual.)

2. Remove muffler and exhaust pipes (A).

3. Remove intake manifold (B). (See Remove Intake

Manifold, Group 10 in this manual.)

4. Remove cylinder heads (C). (See Remove Cylinder

Heads, Group 10 in this manual.)

5. Remove intake and exhaust valves (D). (See Remove

Intake and Exhaust Valves, Group 15 in this manual.)

6. Remove flywheel (E). (See Remove Flywheel, Group

20 in this manual.)

7. Remove camshaft. (See Remove Camshaft, Group 25

in this manual.)

A—Muffler and Exhaust Pipes

B—Intake Manifold

C—Cylinder Heads

D—Intake and Exhaust Valves

E—Flywheel

M36474 -UN-29JAN90

DISASSEMBLE AND INSPECT GOVERNOR

ASSEMBLY

1. Hold cup against flyballs. Measure distance from snap

ring to surface of hub. The distance must be 5.6 mm

(0.22 in.).

If the distance is not correct, replace camshaft assembly.

NOTE: The camshaft and pin are only serviced as an

assembly.

2. The cup (A) must spin freely on the camshaft pin

without excessive play. Replace parts as necessary.

M36308 -UN-29JAN90

M98,2045K,4 -19-21OCT85

M98,2045K,5 -19-21OCT85

Governor/Governor Assembly

CTM2 (19APR90) 45-2 16, 18, 20 & 24HP Onan Engines

130495

3. Remove snap ring to remove hub (A) and cup (B).

4. Inspect cup race for grooved or rough surface.

Replace cup if necessary.

M36309 -UN-29JAN90

5. Remove flyballs. Inspect flyballs for grooved or flat

spots, replace if necessary.

6. Inspect flyball spacer (A) for wear or damage.

Replace camshaft gear if necessary.

NOTE: The flyball spacer, plate, and camshaft gear are

serviced as an assembly only.

IMPORTANT: If camshaft gear is replaced, always

replace crankshaft gear also.

7. Inspect camshaft gear for chipped or broken teeth.

Replace camshaft gear if necessary.

M36310 -UN-29JAN90

IMPORTANT: Be sure to hold camshaft while

removing camshaft gear.

8. Remove gear using a 1 in. deep-well socket, 1 in.

driver disk, and a press.

9. Remove key.

M30688 -UN-14JUL89

M98,2025K,15 -19-09OCT85

M98,2025K,16 -19-09OCT85

M98,2025K,17 -19-11NOV85

Governor/Governor Assembly

CTM2 (19APR90) 45-3 16, 18, 20 & 24HP Onan Engines

130495

DISASSEMBLE AND INSPECT GOVERNOR

LINKAGE

1. Move governor arm. The governor arm must move

freely without excessive play.

2. Inspect fork (A) and governor arm shaft (B) for wear

or bent condition. Replace parts as necessary.

M36475 -UN-29JAN90

3. Pull governor arm shaft outward.

4. Remove ball bearing from governor arm shaft hole

using a magnet.

M36476 -UN-29JAN90

5. If necessary, remove staked ends of fork screws using

a small grinder.

M36477 -UN-29JAN90

6. Remove two screws to remove fork. If screws are

tight, support governor arm shaft (A) and loosen screws

using an impact driver.

7. Remove governor arm shaft.

M36478 -UN-29JAN90

M98,2045K,6 -19-21OCT85

M98,2045K,7 -19-21OCT85

M98,2045K,8 -19-02FEB87

M98,2045K,9 -19-21OCT85

Governor/Governor Linkage

CTM2 (19APR90) 45-4 16, 18, 20 & 24HP Onan Engines

130495

8. Remove seal.

M36479 -UN-29JAN90

9. Remove bushing using a 1/2 in. driver disk and 9/16

in. disk.

M36884 -UN-25JAN90

10. Measure distance from surface of gear cover to pin.

The distance must be 19 mm (0.75 in.). Inspect pin for

damage.

11. If the distance is not correct or pin is damaged,

remove pin.

M36885 -UN-25JAN90M36886 -UN-25JAN90

M98,2045K,10 -19-21OCT85

M98,2045K,11 -19-21OCT85

M98,2045K,12 -19-21OCT85

Governor/Governor Linkage

CTM2 (19APR90) 45-5 16, 18, 20 & 24HP Onan Engines

130495

ASSEMBLE GOVERNOR LINKAGE

1. Install new pin in gear cover until pin is 19 mm (0.75

in.) from surface of gear cover.

M36887 -UN-25JAN90M36885 -UN-25JAN90

2. Install new bushing using a 1/2 in. driver disk and

9/16 in. disk. Push bushing even with bottom of oil seal

bore.

M36884 -UN-25JAN90

3. Install new seal, with lips of seal toward driver, using

a 1 in. driver disk. Push seal even with surface of gear

cover.

M36480 -UN-29JAN90

M98,2045K,13 -19-21OCT85

M98,2045K,14 -19-21OCT85

M98,2045K,15 -19-21OCT85

Governor/Governor Linkage

CTM2 (19APR90) 45-6 16, 18, 20 & 24HP Onan Engines

130495

4. Install governor arm shaft (A).

5. Apply thread lock and sealer (medium strength) on

threads of fork screws.

6. Install fork with bent ends upward. Install and tighten

two screws.

M36478 -UN-29JAN90

7. Support governor arm shaft. Hit end of fork screws

using a punch so screws cannot be removed.

M36888 -UN-25JAN90

IMPORTANT: Ball bearing must be installed for

proper governor shaft operation.

8. Install ball bearing in governor arm shaft hole.

9. Install governor arm shaft (A) in governor arm shaft

hole.

M36889 -UN-25JAN90

M98,2045K,16 -19-21OCT85

M98,2045K,17 -19-21OCT85

M98,2045K,18 -19-21OCT85

Governor/Governor Linkage

CTM2 (19APR90) 45-7 16, 18, 20 & 24HP Onan Engines

130495

ASSEMBLE GOVERNOR ASSEMBLY

1. Install key in camshaft.

2. Install gear with timing mark “O” away from camshaft.

3. Align slot in gear with key in shaft.

4. Push camshaft into gear using a 1-3/8 in. driver disk

and a press until camshaft is even with bottom of gear

surface.

M30756 -UN-14JUL89

5. Apply clean engine oil on camshaft parts before

assembly.

6. Install flyballs in flyball spacer (A) notches.

M36310 -UN-29JAN90

7. Install cup (A), hub (B), and fasten with snap ring.

M36318 -UN-29JAN90

M98,2045K,19 -19-21OCT85

M98,2025K,25 -19-09OCT85

M98,2025K,26 -19-09OCT85

Governor/Governor Assembly

CTM2 (19APR90) 45-8 16, 18, 20 & 24HP Onan Engines

130495

INSTALL GOVERNOR ASSEMBLY AND

GOVERNOR LINKAGE

1. Install camshaft. (See Install Camshaft, Group 25 in

this manual.)

2. Install flywheel (E). (See Install Flywheel, Group 20 in

this manual.)

3. Install intake and exhaust valves (D). (See Install

Intake and Exhaust Valves, Group 15 in this manual.)

4. Install cylinder heads (C). (See Install Cylinder Heads,

Group 10 in this manual.)

5. Install intake manifold (B). (See Install Intake Manifold,

Group 10 in this manual.)

6. Install muffler and exhaust pipes (A). (See Install

Intake Manifold, Group 10 in this manual.)

7. Install engine. (See machine technical manual.)

A—Muffler and Exhaust Pipes

B—Intake Manifold

C—Cylinder Heads

D—Intake and Exhaust Valves

E—Flywheel

M36474 -UN-29JAN90

M98,2045K,20 -19-21OCT85

Governor/Governor Assembly and Linkage

CTM2 (19APR90) 45-9 16, 18, 20 & 24HP Onan Engines

130495

Governor/Governor Assembly and Linkage

CTM2 (19APR90) 45-10 16, 18, 20 & 24HP Onan Engines

130495

SERVICE EQUIPMENT AND TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Name Use

1/2 in. Crowsfoot Wrench To remove carburetor

SERVICE PARTS KITS

The following kits are available through your parts

catalog:

Choke Shaft Kit

Gasket Kit

Carburetor Float Kit

Float Valve And Seat Kit

Idle Needle Kit

Idle Speed Adjusting Screw Kit

Throttle Shaft Kit

Carburetor Repair Kit

SPECIFICATIONS

Item Measurement Specification

Carburetor Float Level Height from edge of bowl 0 to 1 mm (0.0 to 0.04 in.)

Carburetor Float Drop Depth below edge of bowl 5 mm (0.20 in.) Minimum

Breaker Point Gap Opening 0.41 mm (0.016 in.)

M98,2050K,1 -19-21OCT85

M98,2050K,2 -19-21OCT85

M98,2050K,3 -19-21OCT85

Group 50

Carburetor

CTM2 (19APR90) 50-1 16, 18, 20 & 24HP Onan Engines

130495

REMOVE CARBURETOR

NOTE: The carburetor removal includes procedures for

all carburetors. The differences are noted. The

carburetor can be removed with engine in

machine.

1. If equipped, turn reserve fuel lever to OFF position.

2. Remove air cleaner assembly. (See Remove Air

Cleaner in Group 05 of this manual.)

3. If engine is in machine, disconnect fuel line from

carburetor.

4. If engine is in machine, loosen choke cable clamp

screws (A). Disconnect cable from carburetor.

M36985 -UN-25JAN90

5. If engine is in machine, remove clip (A) to disconnect

governor control linkage.

6. Loosen set screw. Remove breaker point cover, if

equipped.

T260 Engine

B43E, B43G, or E48G Engine

M36986 -UN-25JAN90M36987 -UN-25JAN90

M98,2050K,4 -19-21OCT85

M98,2050K,5 -19-21OCT85

M98,2050K,6 -19-02FEB87

Carburetor/Carburetor

CTM2 (19APR90) 50-2 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Be careful not to lose the point plunger

or to allow dirt to enter the exposed

plunger hole.

7. Loosen two set screws. Move point assembly, if

equipped, out of the way for access to carburetor

mounting bolts.

T260 Engine (Early point assembly)

B43E, B43G, OR B48G Engine (Early

M36988 -UN-25JAN90M36989 -UN-25JAN90

8. Loosen two cap screws with JDG-333 Crowsfoot

Wrench or short handled 1/2 in. open-end wrench.

Remove carburetor.

T260 Engine

B43E, B43G, or B48G Engine

M36990 -UN-25JAN90M36991 -UN-25JAN90

M98,2050K,7 -19-11FEB87

M98,2050K,8 -19-21OCT85

Carburetor/Carburetor

CTM2 (19APR90) 50-3 16, 18, 20 & 24HP Onan Engines

130495

9. Remove gasket.

NOTE: If it is necessary to replace the mounting cap

screws on the T260 engine, the intake manifold

must be removed. (See Remove Intake Manifold,

Group 10 in this manual.)

T260 Engine

M36992 -UN-25JAN90

DISASSEMBLE CARBURETOR

NOTE: Carburetor disassembly includes procedures for

all carburetors. The differences are noted.

1. Remove two cap screws. Remove choke control

bracket.

M36954 -UN-25JAN90

2. Remove two screws and choke valve.

M36955 -UN-25JAN90

3. Remove choke valve shaft.

4. Remove foam seal (A) from shaft.

Inspect choke shaft. Replace shaft if it shows excessive

wear or is bent.

M36956 -UN-25JAN90

M98,2050K,9 -19-21OCT85

M98,2050K,10 -19-21OCT85

M98,2050K,11 -19-21OCT85

M98,2050K,12 -19-21OCT85

Carburetor/Carburetor

CTM2 (19APR90) 50-4 16, 18, 20 & 24HP Onan Engines

130495

5. Remove two screws and throttle valve.

M36957 -UN-25JAN90

6. Remove throttle valve shaft.

7. Remove foam seal (A) from shaft.

Inspect throttle shaft. Replace shaft if it shows excessive

wear or is bent.

M36958 -UN-25JAN90

8. Remove four screws to remove air intake.

M36959 -UN-25JAN90

M98,2050K,13 -19-21OCT85

M98,2050K,14 -19-21OCT85

M98,2050K,15 -19-21OCT85

Carburetor/Carburetor

CTM2 (19APR90) 50-5 16, 18, 20 & 24HP Onan Engines

130495

9. Remove and discard gasket.

T260 Engine

B43E, B43G, B48G, P218G or P220G

M36961 -UN-25JAN90M36968 -UN-25JAN90

10. Remove O-ring.

M36960 -UN-25JAN90

11. For T260 engine, remove float retaining screw.

M36964 -UN-25JAN90

M98,2050K,16 -19-02FEB87

M98,2050K,17 -19-21OCT85

M98,2050K,18 -19-21OCT85

Carburetor/Carburetor

CTM2 (19APR90) 50-6 16, 18, 20 & 24HP Onan Engines

130495

12. Remove float, pivot pin, and needle valve.

Inspect needle valve. Replace valve if it is grooved or

pitted.

Check float for dents or leaks. Replace if defective or

loaded with fuel.

T260 Engine

B43E, B43G, B48G, P218G, or P220G

M36965 -UN-25JAN90M36970 -UN-25JAN90

13. Remove seat. Remove washer (A).

Inspect needle seat area for wear or damage. Replace

seat if defective.

T260 Engine

B43E, B43G, B48G, P218G, or P220G

M36966 -UN-25JAN90M36971 -UN-25JAN90

M98,2050K,19 -19-02FEB87

M98,2050K,20 -19-02FEB87

Carburetor/Carburetor

CTM2 (19APR90) 50-7 16, 18, 20 & 24HP Onan Engines

130495

14. For B43E, B43G, B48G, P218G, or P220G engine,

remove slow idle jet.

M36972 -UN-25JAN90

15. Remove reservoir plug and gasket.

T260 Engine

B43E, B43G, B48G, P218G, OR P220G

M36962 -UN-25JAN90M36969 -UN-25JAN90

M98,2050K,21 -19-02FEB87

M98,2050K,22 -19-11FEB87

Carburetor/Carburetor

CTM2 (19APR90) 50-8 16, 18, 20 & 24HP Onan Engines

130495

16. Remove main jet.

Inspect main jet. Replace if damaged.

T260 Engine

B43E, B43G, B48G, P218G, or P220G

M36963 -UN-25JAN90M36973 -UN-25JAN90

17. For P218G or P220G engines, remove plastic cap

from idle mixture screw.

18. Remove idle mixture screw and spring.

Inspect seating surface of mixture screw. Replace if worn

or damaged.

19. Remove idle speed screw (A) and spring.

Replace springs if weak or broken.

M36967 -UN-25JAN90

M98,2050K,23 -19-02FEB87

M98,2050K,24 -19-02FEB87

Carburetor/Carburetor

CTM2 (19APR90) 50-9 16, 18, 20 & 24HP Onan Engines

130495

CLEAN CARBURETOR

IMPORTANT: Never clean holes or passages with

small drill bits or wire because a slight

enlargement or burring of these holes

will change the performance of the

carburetor. No other method of

cleaning other than solvent should be

used.

1. Soak all metal components not replaced in carburetor

cleaner. Do not soak non-metal floats or other non-metal

parts.

2. Clean all carbon from carburetor bore. Be careful not

to plug the idle or main fuel ports.

3. Dry out all passages with low pressure air 240 kPa

(2.4 bar) (35 psi). Make sure all holes and passages are

open. Do not use rags or paper to dry parts.

ASSEMBLE CARBURETOR

NOTE: Carburetor assembly includes procedures for all

carburetors. The differences are noted.

Use new seals, gaskets, and O-ring when assembling

carburetor.

1. Install idle speed screw (A) and spring.

2. Install idle mixture screw and spring. Turn idle mixture

screw in until lightly seated, then back it out 1-1/4 turns.

For P218G and P220G engines, install plastic cap on

idle mixture screw.

M36967 -UN-25JAN90

M98,2050K,25 -19-21OCT85

M98,2050K,26 -19-11FEB87

Carburetor/Carburetor

CTM2 (19APR90) 50-10 16, 18, 20 & 24HP Onan Engines

130495

3. Install main jet.

T260 Engine

B43E, B43G, B48G, P218G, or P220G

M36963 -UN-25JAN90M36973 -UN-25JAN90

4. Install reservoir plug and gasket.

T260 Engine

B43E, B43G, B48G, P218G, or P220G

M36962 -UN-25JAN90M36969 -UN-25JAN90

M98,2050K,27 -19-02FEB87

M98,2050K,28 -19-02FEB87

Carburetor/Carburetor

CTM2 (19APR90) 50-11 16, 18, 20 & 24HP Onan Engines

130495

5. For B43E, G43G, B48G, P218G, or P220G engine,

install slow idle jet.

M36972 -UN-25JAN90

6. Install seat and washer (A).

T260 Engine

B43E, B43G, B48G, P218G, or P220G

M36966 -UN-25JAN90M36971 -UN-25JAN90

M98,2050K,29 -19-02FEB87

M98,2050K,30 -19-01JAN87

Carburetor/Carburetor

CTM2 (19APR90) 50-12 16, 18, 20 & 24HP Onan Engines

130495

7. Install float, pivot pin, and valve. Be sure wire on

valve is hooked over tab on float.

Install float, pivot pin, and valve. Be sure valve is hooked

on float tab.

T260 Engine

B43E, B43G, B48G, P218G, or P220G

M36965 -UN-25JAN90M36970 -UN-25JAN90

8. For T260 engine, fasten float assembly with retaining

screw. Make sure pivot pin is in the groove and that the

float moves freely without binding.

M36964 -UN-25JAN90

M98,2050K,31 -19-02FEB87

M98,2050K,32 -19-21OCT85

Carburetor/Carburetor

CTM2 (19APR90) 50-13 16, 18, 20 & 24HP Onan Engines

130495

When checking float level and float drop, measure to

float body, not seam.

9. Turn carburetor and check float setting using

straightedge. Adjust floats so that they are even with

edge of bowl or no more than 1 mm (0.04 in.) beyond

edge. Bend float tab (A) to adjust.

Turn carburetor and hold pivot pin in place. Check float

setting using a straightedge. Adjust floats so that they

are even with the edge of bowl or no more than 1 mm

(0.04 in.) beyond edge. Bend float tang (A) to adjust. T260 Engine

B43E, B43G, B48G, P218G, or P220G

M36974 -UN-25JAN90M36975 -UN-25JAN90

10. Turn carburetor right side up and measure float drop.

The distance from top of carburetor body to top of float

must be at least 5 mm (0.20 in.). Bend float arm (A) to

adjust. If float drop is adjusted, check float level again.

T260 Engine

B43,E, B43G, B48G, P218G, or P220G

M36983 -UN-25JAN90M36984 -UN-25JAN90

M98,2050K,33 -19-11FEB87

M98,2050K,34 -19-02FEB87

Carburetor/Carburetor

CTM2 (19APR90) 50-14 16, 18, 20 & 24HP Onan Engines

130495

11. Install O-ring on carburetor intake.

M36960 -UN-25JAN90

12. Install gasket.

T260 Engine

B43E, B43G, B48G, P218G, OR P220G

M36961 -UN-25JAN90M36968 -UN-25JAN90

13. Install air intake. Fasten with four screws.

M36959 -UN-25JAN90

M98,2050K,35 -19-21OCT85

M98,2050K,36 -19-02FEB87

M98,2050K,37 -19-21OCT85

Carburetor/Carburetor

CTM2 (19APR90) 50-15 16, 18, 20 & 24HP Onan Engines

130495

14. Apply a small amount of oil to the foam seal (A).

Install foam seal and throttle valve shaft.

M36958 -UN-25JAN90

15. Install throttle valve. Adjust valve plate so that it is

centered in the bore before tightening the two screws.

To center the plate, back off the throttle stop screw and

completely close the throttle lever. Seat the valve plate

by tapping with a small screwdriver, the tighten screws.

M36957 -UN-25JAN90

16. Apply a small amount of oil to the foam seal (A).

Install foam seal and choke valve shaft.

M36956 -UN-25JAN90

17. Install choke valve. Adjust valve plate so that it is

centered in the bore before tightening two screws.

M36955 -UN-25JAN90

M98,2050K,38 -19-21OCT85

M98,2050K,39 -19-21OCT85

M98,2050K,40 -19-21OCT85

M98,2050K,41 -19-21OCT85

Carburetor/Carburetor

CTM2 (19APR90) 50-16 16, 18, 20 & 24HP Onan Engines

130495

18. Connect choke shaft wire and install choke control

bracket. Fasten with two cap screws.

M36954 -UN-25JAN90

INSTALL CARBURETOR

1. Put new gasket on intake manifold. Install carburetor.

T260 Engine

M36992 -UN-25JAN90

2. Fasten carburetor with two cap screws. Tighten with

JDG-333 Crowsfoot Wrench or short handled 1/2 in.

open-end wrench.

T260 Engine

B43E, B43G, or B48G Engine

M36990 -UN-25JAN90M36991 -UN-25JAN90

M98,2050K,42 -19-21OCT85

M98,2050K,43 -19-21OCT85

M98,2050K,44 -19-21OCT85

Carburetor/Carburetor

CTM2 (19APR90) 50-17 16, 18, 20 & 24HP Onan Engines

130495

3. Be sure point plunger (A) and gasket (B) are in place.

Be sure plunger hole (C) is uncovered.

4. Apply thread sealant on threads of set screws and

install breaker point assembly, if equipped.

T260 Engine

M36993 -UN-25JAN90

5. Fasten point assembly, if equipped, with two set

screws.

6. Check point gap. Set gap to 0.41 mm (0.016 in.).

T260 Engine (Early point assembly)

B43E, B43G, or B48G Engine (Early

M36988 -UN-25JAN90M36989 -UN-25JAN90

M98,2050K,45 -19-11FEB87

M98,2050K,46 -19-11FEB87

Carburetor/Carburetor

CTM2 (19APR90) 50-18 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Be sure to position breaker point lead

so cover does not pinch it. Engine will

not run if cover and wire make a short

circuit.

7. Install breaker point cover and tighten screw, if

equipped.

8. If engine is in unit, install clip (A) and connect

governor control linkage.

T260 Engine

B43E, B43G, or B48G Engine

M36986 -UN-25JAN90M36987 -UN-25JAN90

M98,2050K,47 -19-11FEB87

Carburetor/Carburetor

CTM2 (19APR90) 50-19 16, 18, 20 & 24HP Onan Engines

130495

9. If engine is in machine, connect and fasten fuel line to

carburetor with clamp (A).

NOTE: Adjust choke properly for satisfactory engine

starting and operation. The following adjustment

can only be made with engine installed in

machine.

10. Install choke cable in bracket and fasten with screw

(B).

11. Push choke control knob (on instrument panel) in all

the way.

12. Hold choke valve (C) straight up and tighten screw

(D).

13. Pull choke control knob out. Choke valve must be

closed. Push knob in. Valve must be completely open.

Adjust if needed.

14. Check that choke and throttle linkages operate freely.

15. Install air cleaner assembly. (See Install Air Cleaner

in Group 05 of this manual.)

16. Adjust engine speed. (See machine technical

manual.)

M36994 -UN-25JAN90

M98,2050K,48 -19-26NOV85

Carburetor/Carburetor

CTM2 (19APR90) 50-20 16, 18, 20 & 24HP Onan Engines

130495

SPECIFICATIONS

Item Measurement Specification

Lift Bracket Cap Screw Torque 11 ± 3 N·m (97 ± 27 lb-in.)

B43E, B43G, B48G, T260 Engine: Torque 51 ± 3 N·m (38 ± 2 lb-ft)

Flywheel Cap Screw

P218G and P220G Engine: Flywheel Torque 67—75 N·m (50—55 lb-ft)

Cap Screw

REMOVE STATOR

1. Remove engine. (See machine technical manual.)

2. Disconnect spark plug wire and voltage regulator

leads.

3. Remove cap screws to remove lift bracket (A) and

manifold cover (B).

4. Remove four cap screws on T260, P218G, or P220G

engine; five cap screws on B43E, B43G, B48G engine to

remove side shroud (C).

M36445 -UN-29JAN90

5. Loosen hose clamp (A) to disconnect fuel impulse line

(B).

M36290 -UN-29JAN90

M98,2055K,1 -19-11FEB87

M98,2055K,2 -19-02FEB87

M98,2060K,6 -19-05NOV85

Group 55

Stator and Rectifier—Regulator

CTM2 (19APR90) 55-1 16, 18, 20 & 24HP Onan Engines

130495

6. Disconnect governor spring (A).

7. Remove two screws to remove fuel pump (B).

8. Remove five cap screws to remove flywheel shroud

(C).

M36291 -UN-29JAN90

IMPORTANT: Do not hold flywheel from turning with

a pry bar. Doing so can damage the

fins.

9. Fasten locking pliers to ring gear to prevent flywheel

from turning.

NCAUTION: Loosen flywheel cap screw only two

turns. Do not remove cap screw. If cap screw

is removed, flywheel may cause injury when it

comes loose.

10. Loosen cap screw two turns only.

M36292 -UN-29JAN90

M98,2060K,7 -19-05NOV85

M98,2055K,3 -19-22OCT85

Stator and Rectifier—Regulator/Stator

CTM2 (19APR90) 55-2 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Do not pry on flywheel with a

screwdriver. Ceramic magnets and gear

case cover can be damaged.

11. Loosen flywheel using a puller.

12. Remove puller, cap screw, washer, and flywheel.

M36293 -UN-29JAN90

13. Disconnect stator lead from retaining clip (A).

14. Remove three cap screws. Gently pull stator off

mounting posts.

M37155 -UN-25JAN90

INSTALL STATOR

1. Put stator on mounting posts and fasten with three

cap screws. Tighten cap screws evenly so that stator is

held flat against posts.

Connect stator lead in retaining clip (A).

M37155 -UN-25JAN90

M98,2055K,4 -19-22OCT85

M98,2055K,5 -19-22OCT85

M98,2055K,6 -19-22OCT85

Stator and Rectifier—Regulator/Stator

CTM2 (19APR90) 55-3 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Do not lubricate crankshaft taper. The

crankshaft taper must be dry to hold

the flywheel tight.

2. Clean crankshaft taper before installing flywheel.

3. Apply pipe sealant on threads of flywheel cap screw.

4. Align keyway (A) in flywheel with key (B) in crankshaft

and install flywheel.

5. Install washer and cap screw.

IMPORTANT: Do not hold flywheel from turning with

a pry bar in the fins. Doing so may

damage the fins.

6. Fasten locking pliers to ring gear to prevent flywheel

from turning.

7. On B43E, B43G, B48G, T260 engines, tighten cap

screw to 51 ± 3 N·m (38 ± 2 lb-ft).

On P218G and P220G engine, tighten cap screw to

67—75 N·m (50—55 lb-ft).

M36297 -UN-29JAN90M36298 -UN-29JAN90

M98,2060K,73 -19-11FEB87

Stator and Rectifier—Regulator/Stator

CTM2 (19APR90) 55-4 16, 18, 20 & 24HP Onan Engines

130495

8. Install flywheel shroud (C). Fasten with five cap

screws.

9. Install fuel pump (B). Fasten with two screws.

10. Connect governor spring (A) in top hole of arm.

M36291 -UN-29JAN90

11. Connect fuel pump impulse line (B) and fasten with

hose clamp (A).

M36290 -UN-29JAN90

M98,2055K,7 -19-26NOV85

M98,2055K,8 -19-22OCT85

Stator and Rectifier—Regulator/Stator

CTM2 (19APR90) 55-5 16, 18, 20 & 24HP Onan Engines

130495

12. Install side shroud (C). Fasten with four cap screws

on T260, P218G, and P220G engine; five cap screws on

B43E, B43G, or B48G engine.

13. Install manifold cover (B) and lift bracket (A). Fasten

with three cap screws on T260 engine; two cap screws

on B43E, or B48G engine. Tighten lift bracket cap screw

to 11 ± 3 N·m (97 ± 27 lb-in.).

14. Connect spark plug wire and voltage regulator leads.

Install the two stator leads on “AC” terminals and the

battery lead on “B+” terminal of voltage regulator.

15. Install engine. (See machine technical manual.)

T260 Engine Shown

M36445 -UN-29JAN90

REPLACE RECTIFIER-REGULATOR

1. For T260 engine only, remove three cap screw (A) to

remove manifold cover.

M37239 -UN-25JAN90

M98,2055K,9 -19-02FEB87

M98,2055K,10 -19-22OCT85

Stator and Rectifier—Regulator/Replace

CTM2 (19APR90) 55-6 16, 18, 20 & 24HP Onan Engines

130495

2. Disconnect battery lead (A).

3. Disconnect two stator leads (B).

4. Remove cap screw (C).

5. Push regulator toward cap screw; then lift from

shroud.

6. Install new regulator and fasten with cap screw (C).

7. Connect two stator leads (B) to “AC” terminals. T260 Engine (Top Photo)

8. Connect battery lead (A) to “B+” terminal.

9. For T260 engine only, install manifold cover and

fasten with three cap screws. Tighten lift bracket cap

screw to 11 ± 3 N·m (97 ± 27 lb-in.).

B43E, B43G, B48G, P21G, or P220G

M37240 -UN-25JAN90M37241 -UN-25JAN90

M98,2055K,11 -19-02FEB87

Stator and Rectifier—Regulator/Replace

CTM2 (19APR90) 55-7 16, 18, 20 & 24HP Onan Engines

130495

Stator and Rectifier—Regulator/Replace

CTM2 (19APR90) 55-8 16, 18, 20 & 24HP Onan Engines

130495

SERVICE EQUIPMENT AND TOOLS

NOTE: Order tools from the U.S. SERVICE-GARD™ Catalog or from the European Microfiche Tool Catalog

(MTC). Some tools may be available from a local supplier.

Name Use

Volt-Ohm-Amp Meter Check continuity

Armature Growler Check starter armature

13-Ton Puller Set Remove flywheel

Blind Hole Puller Set Pull bushings

Dial Indicator Check armature shaft thrust gap

M98,2060K,1 -19-05NOV85

Group 60

Starter

CTM2 (19APR90) 60-1 16, 18, 20 & 24HP Onan Engines

130495

SPECIFICATIONS

Item Measurement Specification

BENDIX DRIVE STARTER

Starter Pinion Backlash 0.13—0.89 mm (0.005—0.035)

Brushes Wear Length 6.35 mm (0.25 in.) minimum

Armature Lock Nut Torque 30 ± 3 N·m (265 ± 27 lb-in.)

Battery Terminal Nut Torque 6 ± 1 N·m (53 ± 9 lb-in.)

Negative Brush Cap Screw Torque 4.5 ± 0.5 N·m (40 ± 4.5 lb-in.)

End Cap Thru-Bolts Torque 7 ± 1 N·m (62 ± 9 lb-in.)

SOLENOID DRIVE STARTER

Brushes Wear Length 11.5 mm (0.45 in.) minimum

End Cap Thru-Bolts Torque 5.7 ± 1.1 N·m (50 ± 10 lb-in.)

Solenoid Screws Torque 6 ± 1 N·m (53 ± 9 lb-in.)

Armature Shaft Thrust Gap Clearance 0.1 to 0.5 mm (0.004 to 0.020 in.)

Pinion-to-Stop Ring Gap Clearance 0.5 to 2.0 mm (0.020 to 0.079 in.)

Starter Mounting Cap Screws Torque 34 ± 1 N·m (300 ± 9 lb-in.)

B43E, B43G, B48G, T260 Engines: Torque 51 ± 3 N·m (38 ± 2 lb-ft)

Flywheel Mounting Cap Screw

Lift Bracket Cap Screw Torque 11 ± 3 N·m (97 ± 27 lb-in.)

M98,2060K,2 -19-11FEB87

Starter/Specifications

CTM2 (19APR90) 60-2 16, 18, 20 & 24HP Onan Engines

130495

SERVICE PARTS KITS

The following kits are available through your parts

catalog:

Solenoid Kit

Bushing Kit

Brush Kit

Hardware Kit

Clutch Kit

Shift Lever Kit

REMOVE STARTER—B43E, B43G, B48G,

AND T260 ENGINES

NOTE: See Starting Circuit Diagnosis in machine

technical manual before removing starter.

1. Remove engine. (See machine technical manual.)

2. Disconnect spark plug wire and voltage regulator

leads.

3. Remove cap screw to remove lift bracket (A) and

manifold cover (B).

4. Remove four cap screws on T260 engine; five cap

screws on B43E, B43G, or B48G engine, to remove side

shroud (C).

T260 Engine Shown

M36445 -UN-29JAN90

M98,2060K,3 -19-26NOV85

M98,2060K,4 -19-11FEB87

Starter/Starter

CTM2 (19APR90) 60-3 16, 18, 20 & 24HP Onan Engines

130495

5. Loosen hose clamp (A) to disconnect fuel impulse line

(B).

M36290 -UN-29JAN90

6. Disconnect governor spring (A).

7. Remove two screws to remove fuel pump (B).

8. Remove five cap screws to remove flywheel shroud

(C).

M36291 -UN-29JAN90

M98,2060K,6 -19-05NOV85

M98,2060K,7 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-4 16, 18, 20 & 24HP Onan Engines

130495

NOTE: Measure starter pinion gear backlash to check for

wear.

9. Pull starter pinion gear outward until teeth contact

flywheel ring gear. Measure starter pinion gear backlash.

STARTER PINION SPECIFICATIONS

Item New Part

Backlash 0.13—0.89 (0.005—0.035 in.)

If backlash exceeds 0.89 mm (0.035 in.), replace starter

pinion.

M36437 -UN-29JAN90

IMPORTANT: Do not hold flywheel from turning with

a pry bar. Doing so can damage the

fins.

10. Fasten locking pliers to ring gear to prevent flywheel

from turning.

NCAUTION: Loosen flywheel cap screw only two

turns. Do not remove cap screw. If cap screw

is removed, flywheel may cause injury when it

comes loose.

11. Loosen cap screw two turns only.

M36292 -UN-29JAN90

IMPORTANT: Do not pry on flywheel with a

screwdriver. Ceramic magnets and gear

case cover can be damaged.

12. Loosen flywheel using a puller.

13. Remove puller, cap screw, washer, and flywheel.

M36293 -UN-29JAN90

M98,2060K,8 -19-05NOV85

M98,2060K,9 -19-05NOV85

M98,2060K,10 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-5 16, 18, 20 & 24HP Onan Engines

130495

14. Remove two cap screws. Remove starter.

Bendix Drive Starter Shown

M37102 -UN-25JAN90

REMOVE STARTER—P218G AND P220G

ENGINES

NOTE: See Starting Circuit Diagnosis in machine

technical manual before removing starter.

1. Remove engine. (See machine technical manual.)

2. Disconnect spark plug wire.

3. Remove cap screw to remove lift bracket and manifold

cover.

4. Remove cap screws to remove side shroud.

5. Remove cap screws from flywheel shroud. Move

flywheel shroud just far enough to remove starter.

6. Remove two cap screws (A) to remove starter.

M46014 -UN-08JAN90

DISASSEMBLE BENDIX DRIVE STARTER

1. Remove rubber dust cover.

M37104 -UN-25JAN90

M98,2060K,11 -19-05NOV85

M98,2060K,11E -19-11FEB87

M98,2060K,12 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-6 16, 18, 20 & 24HP Onan Engines

130495

2. Remove two thru-bolts.

M37105 -UN-25JAN90

NOTE: Brush springs may snap out of the end cap when

it is removed. Be careful not to lose springs.

3. Remove end cap.

M37106 -UN-25JAN90

4. Remove two cap screws to remove negative brushes.

M37107 -UN-25JAN90

5. Remove nut to remove positive side brushes.

Check all brushes for cracks or excessive wear. Replace

brushes if they are worn shorter than 6.35 mm (0.25 in.).

Inspect springs. Replace springs if they are weak or

broken.

Always replace springs and brushes as a set if any are

defective.

M37108 -UN-25JAN90

M98,2060K,13 -19-05NOV85

M98,2060K,14 -19-05NOV85

M98,2060K,15 -19-05NOV85

M98,2060K,16 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-7 16, 18, 20 & 24HP Onan Engines

130495

6. Pull armature assembly out of housing.

Clean housing and magnets. Magnets must be securely

glued to inside of housing and must be free of cracks.

Replace housing if magnets are loose or cracked.

M37109 -UN-25JAN90

7. Hold armature in soft-jaw vise.

8. Remove lock nut and disassemble parts (I—A).

Clean and check starter drive components for wear or

damage. Inspect bushing in cap (C) for wear.

Replace damaged or worn parts.

A—Armature

B—Thrust Washer

C—Cap

D—Seal

E—Drive Pinion

F—Spacer

G—Spring

H—Washer

I—Lock Nut

M37110 -UN-25JAN90M37111 -UN-25JAN90

M98,2060K,17 -19-05NOV85

M98,2060K,18 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-8 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Do not clean armature with solvent.

Solvent can damage insulation on

windings. Use only mineral spirits and

a brush.

9. Inspect commutator. Look for roughness, burned bars,

or any material which might cause short circuits between

bars. If necessary, clean and touch up with 400 grit

sandpaper. NEVER use emery cloth. Clean all dust from

armature when finished.

10. Test for grounded windings using an ohmmeter or

test light.

Touch probes on commutator and armature core.

Armature windings are connected in series, so only one

commutator bar needs to be checked.

If test shows continuity, a winding is grounded and the

armature must be replaced.

M37112 -UN-25JAN90

11. Test for open circuited windings using an ohmmeter

or test light.

Touch probes on two different commutator bars. If test

shows no continuity, there is an open circuit and the

armature must be replaced.

M37113 -UN-25JAN90

M98,2060K,19 -19-05NOV85

M98,2060K,20 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-9 16, 18, 20 & 24HP Onan Engines

130495

12. Test for short circuited windings using a growler. Put

armature in growler and hold a hacksaw blade above

each slot while slowly rotating armature.

If coil is shorted, the blade will vibrate on the slot.

NOTE: A short circuit most often occurs because of

copper dust or filings between two commutator

segments.

13. If test indicates short circuited windings, clean the

commutator of dust and filings. Check the armature

again. If the test still indicates a short circuit, replace the

armature.

M17166 -UN-24APR89

ASSEMBLE BENDIX DRIVE STARTER

1. Apply a generous film of silicone base grease, such

as GE Versilube 322-L or equivalent, to the worm gear.

2. Apply a thin film of grease to bearing surfaces (A).

M37114 -UN-25JAN90

M98,2060K,21 -19-05NOV85

M98,2060K,22 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-10 16, 18, 20 & 24HP Onan Engines

130495

3. Assemble parts (A-I) in sequence order.

4. Hold armature in a soft-jaw vise. Tighten lock nut to

30 ± 3 N·m (265 ± 27 lb-in.).

A—Armature

B—Thrust Washer

C—Cap

D—Seal

E—Drive Pinion

F—Spacer

G—Spring

H—Washer

I—Lock Nut

M37111 -UN-25JAN90M37115 -UN-25JAN90

5. Put armature assembly in housing. Align notch in cap

with mark on housing.

M37109 -UN-25JAN90

M98,2060K,23 -19-05NOV85

M98,2060K,24 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-11 16, 18, 20 & 24HP Onan Engines

130495

6. Install positive side brushes. Fasten with fiber washer,

flat washer, lock washer, and nut.

Tighten nut to 6 ± 1 N·m (53 ± 9 lb-in.).

7. Install negative brushes. Fasten with cap screws and

tighten to 4.5 ± 0.5 N·m (40 ± 4.5 lb-in.).

8. Install springs.

M37108 -UN-25JAN90M37107 -UN-25JAN90

9. To make temporary brush holders, cut steel banding

into four pieces, 76mm (3 in.) long. Bend flanges 25 mm

(1 in.) long as shown.

10. Push brushes down on the springs and hold them in

place with the four brush holders. Make sure that

chamfered side of brush is up and that the wires do not

rub against the commutator or end cap.

M37116 -UN-25JAN90

11. Apply a light film of grease to bushing (A).

12. Align tab and notch (B); then install end cap on

starter.

M37117 -UN-25JAN90

M98,2060K,25 -19-05NOV85

M98,2060K,26 -19-05NOV85

M98,2060K,27 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-12 16, 18, 20 & 24HP Onan Engines

130495

13. Hold end cap in place and remove four temporary

brush holding clips.

14. Be sure notches on both end caps are aligned with

tabs on housing; then fasten with two thru-bolts. Tighten

bolts to 7 ± 1 N·m (62 ± 9 lb-in.).

M37118 -UN-25JAN90

15. Install rubber dust cover.

M37104 -UN-25JAN90

M98,2060K,28 -19-05NOV85

M98,2060K,29 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-13 16, 18, 20 & 24HP Onan Engines

130495

BENCH TEST SOLENOID DRIVE STARTER

NOTE: Perform bench test before disassembling the

starter motor to determine the cause of the

problem.

IMPORTANT: Never operate motor longer than 20

seconds. Allow at least two minutes for

cooling and battery recovery before

operating again. Overheating, caused

by excessive operation, will seriously

damage starting motor.

1. Connect a 12-volt battery (A) to starter battery

terminal (B) and starter frame (C). Use heavy duty

cables.

2. Connect a remote start switch (D) between switch

terminal (E) and battery terminal (B).

NOTE: A short piece of wire with a small clip on the end

will allow a more positive connection at the

switch terminal.

A—12-Volt Battery

B—Battery Terminal

C—Starter Frame

D—Remote Start Switch

E—Switch Terminal

M37149 -UN-29AUG88

When switch is activated, starter should engage and run.

IF SOLENOID CHATTERS; hold-in winding is

open-circuited.

IF NOTHING HAPPENS; either the solenoid pull-in

winding is open-circuited or mechanical parts are

sticking.

IF SOLENOID ENGAGES, BUT MOTOR DOES NOT

RUN; check solenoid switch continuity, brushes,

armature, and field windings.

Solenoid cannot be repaired, replace it.

M98,2060K,30 -19-05NOV85

M98,2060K,31 -19-26NOV85

Starter/Starter

CTM2 (19APR90) 60-14 16, 18, 20 & 24HP Onan Engines

130495

DISASSEMBLE SOLENOID DRIVE STARTER

1. Remove nut (A) to disconnect field coil lead.

2. Remove two screws (B).

M37150 -UN-25JAN90

3. Remove solenoid switch (A), spring (B), and plunger

(C).

Clean and inspect parts. Replace solenoid assembly if

spring is weak or broken or if other parts are defective.

M37129 -UN-25JAN90

NOTE: If bench test indicated solenoid problems, use

an ohmmeter or test light to check switch.

4. Touch one probe of tester to field coil terminal and

other probe to battery terminal. There should be no

continuity.

M37151 -UN-25JAN90

5. With tester probes still on field coil terminal and

battery terminal, push spring loaded switch button (A).

There should be continuity when button is pushed in all

the way.

M37152 -UN-25JAN90

M98,2060K,32 -19-05NOV85

M98,2060K,33 -19-05NOV85

M98,2060K,34 -19-05NOV85

M98,2060K,35 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-15 16, 18, 20 & 24HP Onan Engines

130495

6. Test for open circuits by touching probes to switch

terminal (A) and to field coil terminal (B). There should

be continuity.

M37153 -UN-25JAN90

7. Touch probes to switch terminal (A) and to solenoid

body (C). There should be continuity.

If the solenoid fails any of the tests, it is defective and

must be replaced.

M37154 -UN-25JAN90

8. Remove two screws (A) and two thru-bolts (B).

M37121 -UN-25JAN90

NOTE: Make a mark across front bracket, field coil, and

end cap to align parts in assembly.

9. Remove end cap. Remove thrust washers (A) which

may stick on end cap or around armature shaft.

Inspect bushing in end cap for excessive wear. Replace

end cap assembly if cap is bent or deformed, or if

bushing is worn.

M37122 -UN-25JAN90

M98,2060K,36 -19-05NOV85

M98,2060K,37 -19-05NOV85

M98,2060K,38 -19-05NOV85

M98,2060K,39 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-16 16, 18, 20 & 24HP Onan Engines

130495

10. Pull springs back to remove two field coil brushes

from brush holder. Remove brush holder.

M37123 -UN-25JAN90

11. Use an ohmmeter or test light to check for continuity.

Touch one probe of tester to brush mounting plate and

other probe to each of the field coil brush holders (A). If

there is continuity, replace the brush holder assembly.

M37139 -UN-29JAN90

12. Pull spring back to remove negative brush.

Measure brush length. Replace brush if worn below

minimum length of 11.5 mm (0.45 in.).

M37124 -UN-25JAN90M37125 -UN-25JAN90

M98,2060K,40 -19-05NOV85

M98,2060K,41 -19-05NOV85

M98,2060K,42 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-17 16, 18, 20 & 24HP Onan Engines

130495

13. To replace negative brush, cut off worn brush and

install new one using a soldering gun and 60-40 rosin

core solder. Newly installed wire should be approximately

same length as the original.

M37140 -UN-29AUG88

14. Remove field coil.

IMPORTANT: Do not clean starter parts with solvent.

Solvent can damage insulation on

windings. Use only mineral spirits and

a brush or wipe clean with a cloth.

Clean and inspect field coil. Check for bare wires or

broken insulation that may cause grounding.

M37126 -UN-25JAN90

15. Test for grounded field winding using an ohmmeter

or test light. Touch one probe of tester to field coil brush

and other probe to field frame. Be sure the brush lead is

not touching the frame. If there is continuity, the coil is

grounded and the field frame assembly must be

replaced.

M36757 -UN-29AUG88

16. Test for open field coil by touching a probe to each

field coil brush. If there is no continuity, the field coil is

open and the field frame assembly must be replaced.

M36758 -UN-29AUG88

M98,2060K,43 -19-05NOV85

M98,2060K,44 -19-05NOV85

M98,2060K,45 -19-05NOV85

M98,2060K,46 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-18 16, 18, 20 & 24HP Onan Engines

130495

17. Check brushes for cracks or excessive wear.

Replace brushes if they are worn shorter than 11.5 mm

(0.45 in.).

M37127 -UN-25JAN90

18. To replace brushes, melt solder from brush lead

connection and install new brush. If additional solder is

needed, use only 60-40 rosin core solder.

M37141 -UN-25JAN90

19. Remove rubber seal (A) and steel plug (B).

M37130 -UN-25JAN90

M98,2060K,47 -19-05NOV85

M98,2060K,48 -19-05NOV85

M98,2060K,49 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-19 16, 18, 20 & 24HP Onan Engines

130495

20. Remove armature (A) and lever (B).

Inspect armature for signs of dragging against pole

shoes.

Inspect lever for cracks or excessive wear. Replace if

defective.

Inspect commutator. Look for roughness, burned bars, or

any material which might cause short circuits between

bars. If necessary, clean and touch up with 400

sandpaper. Never use emery cloth. Clean all dust from

armature when finished.

M37131 -UN-25JAN90

21. Test for grounded windings using an ohmmeter or

test light.

Touch probes on armature core and commutator bar.

Armature windings are connected in series, so only one

commutator bar needs to be checked.

If test shows continuity, a winding is grounded and the

armature is defective.

M37132 -UN-25JAN90

22. Test for open circuited windings using an ohmmeter

or test light.

Touch probes on two different commutator bars. If test

shows no continuity, there is an open circuit and the

armature is defective.

M37133 -UN-25JAN90

M98,2060K,50 -19-05NOV85

M98,2060K,51 -19-05NOV85

M98,2060K,52 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-20 16, 18, 20 & 24HP Onan Engines

130495

23. Test for short circuited windings using a growler. Put

armature in growler and hold a hacksaw blade above

each slot while slowly rotating armature.

If coil is shorted, the blade will vibrate on the slot.

NOTE: A short circuit most often occurs because of

copper dust or filing between two commutator

segments.

24. If test indicates short circuited windings, clean the

commutator of dust and filings. Check the armature

again. If the test still indicates a short circuit, the

armature is defective.

The armature is not serviceable. If any of the tests

indicate grounded, shorted, or open circuited windings,

replace the entire starter.

M17166 -UN-24APR89

IMPORTANT: Do not clean overrunning clutch in

solvent. The clutch contains grease

which would be removed.

NOTE: Check overrunning clutch before removing it from

armature.

25. Turn clutch drive counterclockwise by hand. Pinion

should turn freely.

26. Turn pinion clockwise. A definite resistance should

be felt.

If clutch is free-wheeling in both directions, or if it shows

resistance when turned counterclockwise, it is defective.

Replace overrunning clutch if it is defective or if pinion

gear shows excessive wear or damage.

M37134 -UN-25JAN90

M98,2060K,53 -19-05NOV85

M98,2060K,54 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-21 16, 18, 20 & 24HP Onan Engines

130495

27. Hold armature assembly in a soft-jawed vise. Slide

stop ring (A) down using a piece of pipe.

28. Push snap ring (B) from groove.

M37135 -UN-25JAN90M37136 -UN-25JAN90

29. Remove snap ring (A), stop ring (B), overrunning

clutch (C), and baffle plate (D).

A—Snap Ring

B—Stop Ring

C—Overrunning Clutch

D—Baffle Plate

M37137 -UN-25JAN90

M98,2060K,55 -19-05NOV85

M98,2060K,56 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-22 16, 18, 20 & 24HP Onan Engines

130495

30. Check bushing in front frame for excessive wear.

If it is necessary to remove bushing (A), use a 3/8 in.

blind-hole puller and slide hammer.

NOTE: Thrust washer will be pulled along with bushing.

M37138 -UN-25JAN90

ASSEMBLE SOLENOID DRIVE STARTER

1. If front frame bushing is being replaced, press new

bushing (A) and thrust washer (B) into front frame. Use

a 5/8 in. driver to install washer tight against shoulder of

counterbore.

M37142 -UN-25JAN90

M98,2060K,57 -19-05NOV85

M98,2060K,58 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-23 16, 18, 20 & 24HP Onan Engines

130495

2. Install baffle plate (A), overrunning clutch (B), stop

ring (C), and snap ring (D). Be sure flange of baffle plate

(A) is pointing upward.

3. Put snap ring (D) in groove. Pull stop ring (C) over

the snap ring.

A—Baffle Plate

B—Overrunning Clutch

D—Stop Ring

E—Snap Ring

M37143 -UN-25JAN90

4. Apply Multemp PS No. 2 grease or equivalent to both

ends of armature shaft and to the lever (B). Apply light

oil to the overrunning clutch splines.

5. Install armature assembly (A) and lever (B) into front

frame. Note the position of the lever.

M37131 -UN-25JAN90

6. Install steel plug (B) and rubber seal (A).

M37130 -UN-25JAN90

M98,2060K,59 -19-05NOV85

M98,2060K,60 -19-05NOV85

M98,2060K,61 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-24 16, 18, 20 & 24HP Onan Engines

130495

7. Install field coil. Be sure notch in field coil flange

aligns with rubber seal.

M37126 -UN-25JAN90

8. Install negative brush and hold it in place with the

spring.

M37124 -UN-25JAN90

9. Put brush holder assembly on commutator and install

field coil brushes. Pull springs back and push all three

brushes against commutator, then release springs to hold

brushes.

M37123 -UN-25JAN90

NOTE: Install same number of thrust washers as was

removed when disassembling starter.

10. Apply grease to thrust washers (A) to hold them to

end cap.

11. Install end cap. Be sure slot in end cap aligns with

rubber seal.

M37122 -UN-25JAN90

M98,2060K,62 -19-05NOV85

M98,2060K,63 -19-05NOV85

M98,2060K,64 -19-05NOV85

M98,2060K,65 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-25 16, 18, 20 & 24HP Onan Engines

130495

12. Install two screws (A).

13. Install two thru-bolts (B) and tighten to 5.7 ± 1.1 N·m

(50 ± 10 lb-in.).

M37121 -UN-25JAN90

14. Apply grease to the lever fork and apply light oil to

the plunger (C).

15. Connect plunger (C) to lever fork and install spring

(B) and solenoid switch (A). Note position of switch

terminal on solenoid.

M37129 -UN-25JAN90

16. Fasten solenoid with two screws. Tighten screws to

6 ± 1 N·m (53 ± 9 lb-in.).

17. Connect field coil lead and fasten with nut (A).

M37144 -UN-25JAN90

M98,2060K,66 -19-05NOV85

M98,2060K,67 -19-05NOV85

M98,2060K,68 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-26 16, 18, 20 & 24HP Onan Engines

130495

18. Check armature shaft thrust gap. Set dial indicator

on pinion then raise the armature shaft to determine

thrust gap.

SPECIFICATION

Item Nominal Value

Armature Shaft Thrust Gap 0.1 to 0.5 mm

(0.004 to 0.020 in.)

If the thrust gap is not within the nominal value limits,

add or remove thrust washers shown in Step 10.

M37145 -UN-25JAN90M37146 -UN-25JAN90

NOTE: Normally the pinion clearance will not be affected

by servicing the starter unless the solenoid is

replaced.

19. To check pinion clearance, connect a 12-volt battery

(A) to starter frame (B). Connect a remote switch (C)

between solenoid terminal (D) and battery (A). Use

heavy duty cables.

A—12-Volt Battery

B—Starter Frame

C—Remote Start Switch

D—Solenoid Switch Terminal

M37147 -UN-26APR89

M98,2060K,69 -19-05NOV85

M98,2060K,70 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-27 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: To avoid solenoid overheating, do not

leave solenoid activated longer than

necessary to measure clearance.

20. Close the switch to activate solenoid which will shift

the pinion into cranking position. Measure clearance

between the pinion and stop ring.

SPECIFICATION

Item Nominal Value

Pinion-to-Stop Ring 0.5 to 2.0 mm

Clearance (0.020 to 0.079 in.)

If clearance is not within the nominal value limits, add or

remove shims between solenoid and front frame. See

Step 15.

Adding shims provided with Solenoid Repair Kit,

decreases the amount of clearance.

21. After assembly, perform bench test. (See “Bench

Test Solenoid Drive Starter” in this group.)

M37148 -UN-25JAN90

INSTALL STARTER—P218G AND P220G

ENGINES

1. Install starter. Tighten cap screws (A) to 26 N·m (230

lb-in.).

2. Align flywheel shroud and install cap screws.

3. Install side shroud and cap screws.

4. Install manifold and lift bracket. Tighten cap screw to

11 ± 3 N·m (97 ± 27 lb-in.).

5. Connect spark plug wire.

6. Install engine. (See machine technical manual.)

M46014 -UN-08JAN90

M98,2060K,71 -19-05NOV85

M98,2060K,72A -19-02FEB87

Starter/Starter

CTM2 (19APR90) 60-28 16, 18, 20 & 24HP Onan Engines

130495

INSTALL STARTER—B43E, B43G, B48G,

AND T260 ENGINES

1. Install starter. Tighten two cap screws to 34 ± 1 N·m

(300 ± 9 lb-in.).

Bendix Drive Starter Shown

M36439 -UN-29JAN90

IMPORTANT: Do not lubricate crankshaft taper. The

crankshaft taper must be dry to hold

the flywheel tight.

2. Clean crankshaft taper before installing flywheel.

3. Apply pipe sealant on threads of flywheel cap screw.

4. Align keyway (A) in flywheel with key (B) in crankshaft

and install flywheel.

5. Install washer and cap screw.

IMPORTANT: Do not hold flywheel from turning with

a pry bar in the fins. Doing so may

damage the fins.

6. Fasten locking pliers to ring gear to prevent flywheel

from turning.

7. On B43E, B43G, B48G, T260 engines, tighten cap

screw to 51 ± 3 N·m (38 ± 2 lb-ft).

On P218G and P220G engine, tighten cap screw to

67—75 N·m (50—55 lb-ft).

M36297 -UN-29JAN90M36298 -UN-29JAN90

M98,2060K,72 -19-11FEB87

M98,2060K,73 -19-11FEB87

Starter/Starter

CTM2 (19APR90) 60-29 16, 18, 20 & 24HP Onan Engines

130495

NOTE: For engines with adjustable starter bracket,

measure starter pinion gear backlash using the

following procedure. For all other units with

non-adjustable starter bracket, go to Step 21.

8. Pull starter pinion gear outward until teeth contact

flywheel ring gear. Measure starter pinion gear backlash.

Backlash specification is 0.51 ± 0.38 mm (0.020 ± 0.15

in.).

If backlash is correct, go to Step 21.

9. If backlash is not correct, loosen starter cap screws

(A) and move starter bracket (B) to obtain correct

backlash.

Tighten starter cap screws to hold bracket in position.

Check backlash again.

M36437 -UN-29JAN90M36438 -UN-29JAN90

IMPORTANT: Do not hold flywheel from turning with

a pry bar. Doing so can damage the

fins.

10. Fasten locking pliers to ring gear to prevent flywheel

from turning.

NCAUTION: Loosen flywheel cap screw only two

turns. Do not remove cap screw. If cap screw

is removed, flywheel may cause injury when it

comes loose.

11. Loosen cap screw two turns only.

M36292 -UN-29JAN90

M98,2060K,78 -19-26NOV85

M98,2060K,9 -19-05NOV85

Starter/Starter

CTM2 (19APR90) 60-30 16, 18, 20 & 24HP Onan Engines

130495

IMPORTANT: Do not pry on flywheel with a

screwdriver. Ceramic magnets and gear

case cover can be damaged.

12. Loosen flywheel using a puller.

13. Remove puller, cap screw, washer, and flywheel.

M36293 -UN-29JAN90

14. Tighten starter cap screws to 34 ± 1 N·m (300 ± 9

lb-in.).

M36439 -UN-29JAN90

IMPORTANT: Do not lubricate crankshaft taper. The

crankshaft taper must be dry to hold

the flywheel tight.

15. Clean crankshaft taper before installing flywheel.

16. Apply pipe sealant on threads of flywheel cap screw.

17. Align keyway (A) in flywheel with key (B) in

crankshaft and install flywheel.

18. Install washer and cap screw.

IMPORTANT: Do not hold flywheel from turning with

a prybar in the fins. Doing so may

damage the fins.

19. Fasten locking pliers to ring gear to prevent flywheel

from turning.

20. Tighten cap screw to 51 ± 3 N·m (38 ± 2 lb-ft).

M36297 -UN-29JAN90M36298 -UN-29JAN90

M98,2060K,10 -19-05NOV85

M98,2060K,79 -19-26NOV85

M98,2060K,80 -19-26NOV85

Starter/Starter

CTM2 (19APR90) 60-31 16, 18, 20 & 24HP Onan Engines

130495

21. Install flywheel shroud (C). Fasten with five cap

screws.

22. Install fuel pump (B). Fasten with two screws.

23. Connect governor spring (A) in top hole of arm.

M36291 -UN-29JAN90

24. Connect fuel pump impulse line (B) and fasten with

hose clamp (A).

M36290 -UN-29JAN90

M98,2060K,75 -19-26NOV85

M98,2060K,76 -19-26NOV85

Starter/Starter

CTM2 (19APR90) 60-32 16, 18, 20 & 24HP Onan Engines

130495

25. Install side shroud (C). Fasten with four cap screws

on T260 engine; five cap screws on B43E, B43G, or

B48G engine.

26. Install manifold cover (B) and lift bracket (A). Fasten

with three cap screws on T260 engine; two cap screws

on B43E, B43G, or B48G engine. Tighten lift bracket cap

screw to 11 ± 3 N·m (97 ± 27 lb-in.).

27. Connect spark plug wire and voltage regulator leads.

Install the two stator leads on “AC” terminals and the

battery lead on “B+” terminal of voltage regulator.

28. Install engine. (See machine technical manual.)

T260 Engine Shown

M36445 -UN-29JAN90

M98,2060K,77 -19-26NOV85

Starter/Starter

CTM2 (19APR90) 60-33 16, 18, 20 & 24HP Onan Engines

130495

Starter/Starter

CTM2 (19APR90) 60-34 16, 18, 20 & 24HP Onan Engines

130495

REPLACE BREAKER POINTS AND

CONDENSER—B43E, B43G, B48G, AND

T260 ENGINES

NOTE: On later engines, the condenser is located on

side of air filter bracket.

1. Remove air cleaner assembly. (See Remove Air

Cleaner in Group 05 in this manual.)

2. Remove breaker point cover.

M37242 -UN-25JAN90

3. Remove two set screws to remove breaker points.

4. Loosen screw (A) to disconnect coil and condenser

leads.

5. Remove screw (B) to remove condenser.

6. Install new condenser and point assembly. Apply

thread sealant on threads of set screws and fasten

breaker points.

Early Point Assembly Shown

M37243 -UN-25JAN90

7. Check breaker point gap. Turn engine flywheel until

points are at their widest gap. Adjust gap to 0.41 mm

(0.016 in.) using a flat feeler gauge.

M37244 -UN-25JAN90

M98,2065K,1 -19-02FEB87

M98,2065K,2 -19-05NOV85

M98,2065K,3 -19-05NOV85

Group 65

Ignition System

CTM2 (19APR90) 65-1 16, 18, 20 & 24HP Onan Engines

130495

8. Be sure coil lead wire is in notch in the base; then

install breaker point cover. Tighten cover set screw snug

only so cover is not crushed or deformed.

9. Install air cleaner assembly. (See Install Air Cleaner in

Group 05 in this manual.)

M37242 -UN-25JAN90

REPLACE IGNITION COIL—B43E, B43G,

B48G, AND T260 ENGINES

1. Remove air cleaner assembly. (See Remove Air

Cleaner in Group 05 in this manual.)

2. Disconnect spark plug wires (A).

3. Loosen screw (B) to remove coil.

4. Remove wires (C) and (D).

5. To install coil, fasten breaker point lead to negative (-) T260 Engine (Top Photo)

terminal (D) and ignition switch lead to positive (+)

terminal (C).

6. Install coil and fasten with screw clamp (B).

7. Connect spark plug wires (A).

8. Install air cleaner assembly. (See Install Air Cleaner in

Group 05 in this manual.)

B43E, B43G, B48G Engine (Bottom

M37156 -UN-25JAN90M37157 -UN-25JAN90

M98,2065K,4 -19-05NOV85

M98,2065K,5 -19-11FEB87

Ignition System/Ignition Coil

CTM2 (19APR90) 65-2 16, 18, 20 & 24HP Onan Engines

130495

REPLACE IGNITION COIL—P218G AND

P220G ENGINES

1. Remove air cleaner assembly. (See Remove Air

Cleaner in Group 05 in this manual.)

2. Disconnect wire leads (A—F).

3. Remove two cap screws to remove ignition coil.

4. Install ignition coil and two cap screws.

5. Connect wire leads and install air cleaner assembly.

(See Install Air Cleaner in Group 05 in this manual.)

A—Spark Plug Wire

B—Spark Plug Wire

C—Condenser Wire

D—Wiring Harness (Key Switch)

E—Orange Wire (Ignition Coil)

F—Black Wire (Ignition Coil)

M46015 -UN-08JAN90

REPLACE IGNITION MODULE AND

MAGNETIC RING—P218G AND P220G

ENGINES

1. Remove air cleaner assembly. (See Group 05 in this

manual.)

2. Remove flywheel. (See Group 20 in this manual.)

3. Remove three cap screws. Gently pull stator (A) off

mounting posts.

M46016 -UN-08JAN90

M98,2065K,6 -19-11FEB87

M98,2065K,7 -19-11FEB87

Ignition System/Ignition Coil

CTM2 (19APR90) 65-3 16, 18, 20 & 24HP Onan Engines

130495

4. Remove key (A) and magnetic ring (B).

5. Remove two cap screws to remove ignition coil (C).

6. Install coil (C), magnetic ring (B)—marked

“FLYWHEEL SIDE”, and key (A).

7. Install starter and cap screws.

8. Install flywheel. (See Group 20 in this manual.)

9. Install air cleaner. (See Group 05 in this manual.)

M46017 -UN-08JAN90

M98,2065K,8 -19-02FEB87

Ignition System/Ignition Coil

CTM2 (19APR90) 65-4 16, 18, 20 & 24HP Onan Engines

130495

Page

Group 00— . . . . . . . . . . . . . . . . . . . . . . . . . .

Introduction . . . . . . . . . . . . . . . . . . . . . . . . 00-1

About This Manual . . . . . . . . . . . . . . . . . . . 00-2

Engine Serial Number Plate . . . . . . . . . . . . . 00-3

Engine Specifications . . . . . . . . . . . . . . . . . 00-3

Engine Application Chart . . . . . . . . . . . . . . . 00-4

Hardware Torque Specifications . . . . . . . . . . 00-4

Group 05—Air Cleaner and Breather

Specifications . . . . . . . . . . . . . . . . . . . . . . 05-1

Air Cleaner

Remove . . . . . . . . . . . . . . . . . . . . . . . . 05-1

Install . . . . . . . . . . . . . . . . . . . . . . . . . . 05-3

Breather, Repair

T260 Engine . . . . . . . . . . . . . . . . . . . . . 05-4

B43E, B43G, or B48G, Engines . . . . . . . . . 05-5

Group 10—Intake Manifold and Cylinder Heads

Service Equipment and Tools . . . . . . . . . . . . 10-1

Service Parts Kits . . . . . . . . . . . . . . . . . . . 10-1

Specifications . . . . . . . . . . . . . . . . . . . . . . 10-2

Intake Manifold

Remove . . . . . . . . . . . . . . . . . . . . . . . . 10-2

Install . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4

Cylinder Head

Remove . . . . . . . . . . . . . . . . . . . . . . . . 10-8

Install . . . . . . . . . . . . . . . . . . . . . . . . . 10-11

Group 15—Intake and Exhaust Valves

Essential Tools . . . . . . . . . . . . . . . . . . . . . 15-1

Service Equipment and Tools . . . . . . . . . . . . 15-1

Service Parts Kits . . . . . . . . . . . . . . . . . . . 15-2

Specifications . . . . . . . . . . . . . . . . . . . . . . 15-3

Intake and Exhaust Valves

Remove . . . . . . . . . . . . . . . . . . . . . . . . 15-5

Install . . . . . . . . . . . . . . . . . . . . . . . . . 15-12

Measure and Adjust Valve Clearance . . . . 15-15

Group 20—Flywheel

Service Equipment and Tools . . . . . . . . . . . . 20-1

Other Material . . . . . . . . . . . . . . . . . . . . . . 20-1

Page

Specifications . . . . . . . . . . . . . . . . . . . . . . 20-1

Flywheel

Remove . . . . . . . . . . . . . . . . . . . . . . . . 20-2

Install . . . . . . . . . . . . . . . . . . . . . . . . . . 20-4

Group 25—Camshaft

Essential Tools . . . . . . . . . . . . . . . . . . . . . 25-1

Service Equipment and Tools . . . . . . . . . . . . 25-1

Other Material . . . . . . . . . . . . . . . . . . . . . . 25-1

Service Parts Kits . . . . . . . . . . . . . . . . . . . 25-2

Specifications . . . . . . . . . . . . . . . . . . . . . . 25-3

Camshaft

Remove . . . . . . . . . . . . . . . . . . . . . . . . 25-4

Disassemble and Inspect . . . . . . . . . . . . . 25-7

Assemble . . . . . . . . . . . . . . . . . . . . . . 25-11

Install . . . . . . . . . . . . . . . . . . . . . . . . . 25-13

Group 30—Connecting Rods and Pistons

Service Equipment and Tools . . . . . . . . . . . . 30-1

Other Material . . . . . . . . . . . . . . . . . . . . . . 30-1

Service Parts Kits . . . . . . . . . . . . . . . . . . . 30-1

Specifications . . . . . . . . . . . . . . . . . . . . . . 30-2

Connecting Rod

Measure End Play . . . . . . . . . . . . . . . . . . 30-4

Measure Bearing Clearance . . . . . . . . . . . 30-7

Pistons and Connecting Rods

Remove . . . . . . . . . . . . . . . . . . . . . . . . 30-9

Inspect . . . . . . . . . . . . . . . . . . . . . . . . 30-13

Deglaze Cylinder Bores . . . . . . . . . . . . . 30-21

Assemble . . . . . . . . . . . . . . . . . . . . . . 30-21

Install . . . . . . . . . . . . . . . . . . . . . . . . . 30-23

Group 35—Crankshaft and Main Bearings

Essential Tools . . . . . . . . . . . . . . . . . . . . . 35-1

Service Equipment and Tools . . . . . . . . . . . . 35-1

Other Material . . . . . . . . . . . . . . . . . . . . . . 35-1

Service Parts Kits . . . . . . . . . . . . . . . . . . . 35-2

Specifications . . . . . . . . . . . . . . . . . . . . . . 35-2

Continued on next page

DEERE & COMPANY

Moline, Illinois

A John Deere ILLUSTRUCTION™ Manual

All information, illustrations and specifications in this manual are based on

the latest information available at the time of publication. The right is

reserved to make changes at any time without notice.

CTM2-19-19APR90

Contents

CTM2 (19APR90) i16, 18, 20 & 24HP Onan Engines

130495

Page

Crankshaft and Main Bearings

Remove . . . . . . . . . . . . . . . . . . . . . . . . 35-3

Inspect . . . . . . . . . . . . . . . . . . . . . . . . . 35-6

Install . . . . . . . . . . . . . . . . . . . . . . . . . . 35-9

Group 40—Lubrication System

Essential Tools . . . . . . . . . . . . . . . . . . . . . 40-1

Service Equipment and Tools . . . . . . . . . . . . 40-1

Other Material . . . . . . . . . . . . . . . . . . . . . . 40-1

Service Parts Kits . . . . . . . . . . . . . . . . . . . 40-2

Specifications . . . . . . . . . . . . . . . . . . . . . . 40-3

Oil Pump

Remove . . . . . . . . . . . . . . . . . . . . . . . . 40-4

Disassemble and Inspect . . . . . . . . . . . . . 40-6

Assemble . . . . . . . . . . . . . . . . . . . . . . . 40-7

Install . . . . . . . . . . . . . . . . . . . . . . . . . . 40-7

Oil Pressure Regulating Valve

Remove . . . . . . . . . . . . . . . . . . . . . . . 40-10

Install . . . . . . . . . . . . . . . . . . . . . . . . . 40-12

Oil Base

Remove and Inspect . . . . . . . . . . . . . . . 40-14

Install . . . . . . . . . . . . . . . . . . . . . . . . . 40-16

Oil Filter Adapter

Remove . . . . . . . . . . . . . . . . . . . . . . . 40-21

Install . . . . . . . . . . . . . . . . . . . . . . . . . 40-22

Oil Line Adapter

Remove . . . . . . . . . . . . . . . . . . . . . . . 40-24

Install . . . . . . . . . . . . . . . . . . . . . . . . . 40-25

Group 45—Governor

Service Equipment and Tools . . . . . . . . . . . . 45-1

Other Material . . . . . . . . . . . . . . . . . . . . . . 45-1

Service Parts Kits . . . . . . . . . . . . . . . . . . . 45-1

Specifications . . . . . . . . . . . . . . . . . . . . . . 45-1

Governor Assembly and Linkage

Remove . . . . . . . . . . . . . . . . . . . . . . . . 45-2

Governor Assembly

Disassemble and Inspect . . . . . . . . . . . . . 45-2

Governor Linkage

Disassemble and Inspect . . . . . . . . . . . . . 45-4

Assemble . . . . . . . . . . . . . . . . . . . . . . . 45-6

Governor Assembly

Assemble . . . . . . . . . . . . . . . . . . . . . . . 45-8

Governor Assembly and Linkage

Install . . . . . . . . . . . . . . . . . . . . . . . . . . 45-9

Group 50—Carburetor

Service Equipment and Tools . . . . . . . . . . . . 50-1

Service Parts Kits . . . . . . . . . . . . . . . . . . . 50-1

Specifications . . . . . . . . . . . . . . . . . . . . . . 50-1

Page

Carburetor

Remove . . . . . . . . . . . . . . . . . . . . . . . . 50-2

Disassemble . . . . . . . . . . . . . . . . . . . . . 50-4

Clean . . . . . . . . . . . . . . . . . . . . . . . . . 50-10

Assemble . . . . . . . . . . . . . . . . . . . . . . 50-10

Install . . . . . . . . . . . . . . . . . . . . . . . . . 50-17

Group 55—Stator and Rectifier—Regulator

Specifications . . . . . . . . . . . . . . . . . . . . . . 55-1

Stator

Remove . . . . . . . . . . . . . . . . . . . . . . . . 55-1

Install . . . . . . . . . . . . . . . . . . . . . . . . . . 55-3

Rectifier-Regulator

Replace . . . . . . . . . . . . . . . . . . . . . . . . . . 55-6

Group 60—Starter

Service Equipment and Tools . . . . . . . . . . . . 60-1

Specifications . . . . . . . . . . . . . . . . . . . . . . 60-2

Service Parts Kits . . . . . . . . . . . . . . . . . . . 60-3

Starter

Remove . . . . . . . . . . . . . . . . . . . . . . . . 60-3

Repair Bendix Drive Starter . . . . . . . . . . . 60-6

Repair Solenoid Drive Starter . . . . . . . . . 60-15

Install . . . . . . . . . . . . . . . . . . . . . . . . . 60-28

Group 65—Ignition System

Breaker Points and Condenser

Replace . . . . . . . . . . . . . . . . . . . . . . . . . 65-1

Ignition Coil

Replace . . . . . . . . . . . . . . . . . . . . . . . . . 65-2

Contents

CTM2 (19APR90) ii 16, 18, 20 & 24HP Onan Engines

130495

CTM2 16 18 20 24 HP Onan Engines

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