Service Manual060306 2500 914 0500 Onan 2EGMBB 2.5EGMBG Home Site Portable Genset Manual (03 2006)

User Manual: 914-0500 Onan 2EGMBB 2.5EGMBG HomeSite Portable Genset Service manual (03-2006)

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Service Manual
HomeSite Power
2400 (2EGMBB-5267)
3500 (2.5EGMBG-5268)
Portable Generator Set

Printed in U. S. A.

03-06

914-0500

Redistribution or publication of this document,
by any means, is strictly prohibited.

SAFETY PRECAUTIONS
Thoroughly read the OPERATOR’S MANUAL
before operating the generator set. Safe
operation and top performance can only be
attained when equipment is operated and
maintained properly.
The following symbols, found throughout this
manual, alert you to potentially dangerous
conditions to operators, service personnel and
equipment.

Gasoline is Flammable / Explosive
• Refuel the generator set outdoors only.
• Static electric sparks caused by fuel flowing
through a service station pump nozzle can
ignite gasoline. Never fill the generator set
with a service station pump nozzle. Instead,
fill a safety tank sitting on the ground and
then slowly transfer fuel to the generator set
from the safety tank.
• DO NOT fill fuel tanks while the engine is
running. A hot engine can ignite the fuel.
• To prevent fire due to fuel leakage, always
close the fuel valve and let the generator set
cool before transporting it or storing it in a
confined space.
• DO NOT SMOKE OR ALLOW AN OPEN
FLAME near the generator set. Keep flames,
sparks, electrical switches, pilot lights,
electrical arcs, arc-producing equipment and
all other sources of ignition well away.

This symbol alerts you to an
immediate hazard that will result in severe
personal injury or death.
This symbol alerts you to a
hazard or unsafe practice that can result in
severe personal injury or death.
This symbol alerts you to a
hazard or unsafe practice that can result in
personal injury or damage to equipment or
property.
Electricity, fuel, exhaust, moving parts and
batteries present hazards against which
precautions must to taken to prevent severe
personal injury or death.

Generator Voltage is Deadly
• DO NOT CONNECT THE GENERATOR
SET DIRECTLY TO ANY BUILDING
ELECTRICAL SYSTEM. Back-feed could
cause electrocution of utility line workers and
damage to equipment. An approved
switching device must be used to prevent
interconnections. A trained and experienced
electrician must make electrical connections
when the generator set is used for
emergency power.
• Make sure clothing, shoes and skin are dry
when handling electrical equipment.
• Never operate the generator set in rain or
snow or when it is sitting on wet ground.

Exhaust Gas Is Deadly
• Operate the generator set outdoors only.
Stay away from the exhaust outlet.

• Make sure generator set exhaust will not
enter windows, doors, vents or air intakes of
adjacent buildings, vehicles or boats.
• NEVER USE THE GENERTOR SET
INSIDE a home, garage, crawl space,
barn, shed, cabin, boat, boat house, RV or
tent, or in a confined outdoor space such as
an alley, ditch, parking garage or courtyard,
or in any other space where exhaust can
accumulate. Note that HAZARDOUS
CARBON MONOXIDE LEVELS FROM
ENGINE EXHAUST CAN ACCUMULATE
INDOORS EVEN WHEN ALL WINDOWS
AND DOORS ARE OPEN AND FANS ARE
RUNNING.

Moving Parts Can Cause Severe
Personal Injury or Death
• Before performing any maintenance on the
generator set, disconnect the spark plug
wire.
• Always keep hands away from moving parts.
• Do not wear loose clothing or jewelry while
servicing the generator set. Loose clothing
and jewelry can become caught in moving
parts. Jewelry can short out electrical
contacts causing sparks, flame and electrical
shock.
• Make sure that fasteners and clamps on the
generator set are tight. Keep guards in
position over fans, rotors, etc.
a
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by any means, is strictly prohibited.

SAFETY PRECAUTIONS
• Benzene and lead may be found in gasoline

Battery Gases are explosive
• Wear

safety glasses when servicing
batteries.
• Do not smoke.
• To reduce arcing when disconnecting or
reconnecting battery cables, always
disconnect the negative (–) cable of the
battery first and reconnect it last.

•

General Precautions
•

• Keep children away from the generator set.
• Wear hearing protection when near an
operating generator set.

• Keep a multi-class ABC fire extinguisher

•

readily at hand. Class A fires involve
ordinary combustible materials such as
wood and cloth. Class B fires involve
combustible and flammable liquids and
gaseous fuels. Class C fires involve live
electrical equipment. (ref. NFPA No. 10)

•

and have been identified by some state and
federal agencies as causing cancer or
reproductive toxicity. Do not ingest, inhale or
contact gasoline.
Used engine oils have been identified by
some state and federal agencies as causing
cancer or reproductive toxicity. Do not ingest,
inhale or contact used engine oil or its
vapors.
Keep the generator set clean and dry at all
times. Excess grease and oil can catch fire
and/or accumulate dirt, which can cause
overheating.
Do not store anything on the generator set,
such as oil cans, oily rags, chains or wooden
blocks. A fire could result or operation could
be adversely affected
Do not work on the generator set when you
are mentally or physically fatigued or have
consumed alcohol or drugs.

Improper service or repairs can create an unsafe condition that
can cause your customer or others to be seriously hurt or killed.
Follow the procedures and precautions in this manual and other
service materials carefully.

Failure to properly follow instructions and precautions can cause
you to be seriously hurt or killed.
Follow the procedures and precautions in this manual carefully.

b
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by any means, is strictly prohibited.

TABLE OF CONTENTS
Title

Page

SECTION 1 INTRODUCTION
1-1 Generator Components
1-2 Specifications
SECTION 2 DIMENSIONS AND TORQUE
2-1 Engine Dimensions
2-2 Generator Dimensions
2-3 Torque Specification
2-4 Standard Torques Specification
SECTION 3 MAINTENANCE
3-1 Maintenance Schedule
3-2 Engine Oil
3-3 Air Cleaner
3-4 Fuel Sediment Cup Cleaning
3-5 Spark Arrester
3-6 Spark Plug
3-7 Valve Clearance
3-8 Governor
SECTION 4 DISASSEMBLY AND SERVICE
4-1 Troubleshooting
4-1-1 Hard Starting
4-1-2 Low Power
4-1-3 Speed Unstable
4-1-4 Low Speed Voltage
4-1-5 Exhaust Color Abnormal
4-1-6 No AC Output Voltage
4-1-7 No DC Output Voltage
4-2 Preparing to Service
4-2-1 Safety Considerations
4-2-2 Special Tools
4-3 Disassembly Chart
4-4 Engine
4-4-1 Crankshaft / Pistion
4-4-2 Flywheel
4-4-3 Cylinder head / Valves
4-4-4 Recoil Starter / Fan Cover
4-4-5 Air Cleaner
4-4-6 Carburetor
4-5 Generator
4-5-1 Fuel Tank
4-5-2 Muffler
4-5-3 Generator
4-5-4 Control Panel
SECTION 5 WIRING DIAGRAMS
5-1 The Wiring Diagram of 2400
5-2 The Wiring Diagram of 3500

1
1
3
4
4
6
6
6
7
7
8
9
10
10
11
12
12
13
13
13
14
15
16
17
18
18
19
19
19
20
21
21
27
29
33
36
37
38
38
39
40
44
50
50
51
c
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SECTION 1. INTRODUCTION
1-1 Generator Components
CHOKE
LEVER

FUEL
FUEL TANK CAP
GAUGE

DC BREAKER RESET SWITCH
AC BREAKER
RESET SWITCH

FUEL
VALVE

EARTH
GROUND
LUG
AIR CLEANER
AC VOLTMETER
12 VOLT DC
TERMINALS

RECOIL STARTER GRIP

ON/OFF
SWITCH

120VAC RECEPTACLE
(GFCI)

SPARK
PLUG
BOOT

MUFFLER

FIGURE 1. 2400 COMPONENT LOCATIONS

-1Redistribution or publication of this document,
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SECTION 1. INTRODUCTION

FUEL
GAUGE

DC BREAKER RESET SWITCH

FUEL TANK CAP

AC BREAKER
RESET SWITCH
CHOKE
LEVER

EARTH
GROUND
LUG
AC BREAKER
RESET SWITCH

FUEL
VALVE

AC RECEPTACLE
(240VAC)

AIR CLEANER

AC VOLTMETER

RECOIL STARTER GRIP

VOLTAGE SELECT
12 VOLT DC
SWITCHE
TERMINALS
ON/OFF
120VAC RECEPTACLE
SWITCH
(GFCI)

SPARK
PLUG
BOOT

MUFFLER

FIGURE 2. 3500 COMPONENT LOCATIONS

-2Redistribution or publication of this document,
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SECTION 1. INTRODUCTION
1-2 Specifications
2400

3500

60 Hz

120 Volts

120 / 240 Volts

Rated Power

2000 Watts

2500 Watts

Rated Current

16.6 Amps

20.8 / 10.4 Amps

12 VDC / 8.3 Amps

GENERATOR
AC OUTPUT:
Frequency (Hertz)
Voltage

DC OUTPUT:
ENGINE
Engine Type

Single Cylinder, Forced Air Cooling, 4-Stroke

Engine Speed (RPM)

3600

Gasoline

0.63 US qt (0.6 L)

Spark Plug Type

F7RTC

Spark Plug Gap

0.028 in. (0.7 mm)

0.0039 /0.006 inches
(0.10/ 0.15 mm)

0.0039 /0.006 inches
(0.10 / 0.15 mm)

20° BTDC

Starting System

Recoil

Displacement

197 cc

99.9 lb (45 kg)

106.6 lb (48 kg)

Length

24.1 inches (612 mm)

Width

19.6 inches (497 mm）

Height

19.3 inches (490 mm)

4.0 US gal (15 L)

13 Hours

12 Hours

Fuel
Engine Oil Capacity

Engine Valve Lash
(Intake / Exhaust)
Ignition Timing

(fixed)

GENERATOR SET
Dry Weight
Dimensions:

Fuel Tank Capacity
Operating Time at Rated Output

-3Redistribution or publication of this document,
by any means, is strictly prohibited.

SECTION 2. DIMENSIONS AND TORQUE
2-1 Engine Dimensions
2400
Part
Engine

Item
Maximum speed
Idle speed
Cylinder compression

Cylinder

Sleeve I.D.

Cylinder head

Warpage

Piston

Skirt O.D.

Factory Specification
3750±150 rpm
1400±150 rpm
6.0-8.5 kg/cm (1.5 –
2.13 kg/in)at 600 rpm

Allowable limit
-

68.015 mm
(2.6778 in)

68.165 mm
(2.6837 in)

18.002 mm
(0.7087 in)
17.998 mm
(0.7086 in)

0.10 mm
(0.004 in)
67.845 mm
(2.6711 in)
0.12 mm
(0.005 in)
18.048 mm
(0.7105 in)
17.954 mm
(0.7068 in)

Piston -to- piston pin bore
clearance

0.004-0.016 mm
(0.00016-0.0006 in)

0.06 mm
(0.002in)

Ring side clearance
Top/second/oil

0.015-0.045 mm
(0.0006-0.0018 in)

0.15 mm
(0.0006 in)

67.985 mm
(2.6766 in)

Piston-to-cylinder clearance

0.030-0.050 mm
(0.0012-0.0020 in)

Piston pin bore I.D.
Pin O.D.

Piston rings

Ring end gap

Top/ second
Oil

0.2-0.4 mm
(0.008-0.016 in)

1.0 mm
(0.04 in)

Ring Width

Top/ second

1.5 mm
(0.06 in)
2.5 mm
(0.10 in)

1.37 mm
(0.054 in)
2.37 mm
(0.093 in)

Small end I.D.
(Pin End)

18.007 mm
(0.7089 in)

18.07 mm
(0.711 in)

Big end I.D.
(Crankshaft)

30.015 mm
(1.1817 in)

30.0667 mm
(1.1837 in)

0.030-0.050 mm
(0.0012-0.0020 in)

0.12 mm
(0.0048 in)

0.1-0.7 mm
(0.004-0.028 in)

1.1 mm
(0.043 in)

29.985 mm
(1.181 in)

29.92 mm
(1.178 in)

Oil
Connecting
rod

Big end oil clearance
Big end side clearance

Crankshaft

Crankshaft O.D.
(Connecting rod Big end)

-4Redistribution or publication of this document,
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SECTION 2. DIMENSIONS AND TORQUE
2400
Part

Item

Valves

Valve Lash

Factory Specification
IN
EX

Stem O.D.

IN
EX

Guide I.D.

IN/ EX

Stem clearance

IN
EX

Seat width
Spring fee length
Camshaft

Cam height

IN
EX

Camshaft O.D.
Crankcase
cover
Spark plug

Camshaft-holder I.D.
Gap

Ignition coil

Resistance
Air gap

Primary coil
Secondary coil
(at flywheel)

0.10±0.02 mm
(0.004±0.001 in)
0.15±0.02 mm
(0.006±0.001 in)
5.48 mm
(0.216 in)
5.47 mm
(0.215 in)
5.50 mm
(0.217 in)
0.02-0.044 mm
(0.0008-0.0017 in)
0.06-0.087 mm
(0.0024-0.0034 in)
0.8 mm
(0.03 in)
30.0 mm
(1.18 in)
27.7 mm
(1.09 in)
27.75 mm
(1.093 in)
13.984 mm
(0.5506 in)
14.0 mm
(0.55 in)
0.7-0.8 mm
(0.028-0.031 in)
0.8-1.0 Ω
5.9-7.1 KΩ
0.4±0.2 mm
(0.016±0.008 in)

Allowable limit
5.318 mm
(0.2094 in)
5.275 mm
(0.2077 in)
5.572 mm
(0.2194 in)
0.10mm
(0.004 in)
0.12 mm
(0.005 in)
2.0mm
(0.08 in)
28.5 mm
(1.122 in)
27.45 mm
(1.081 in)
27.5 mm
(1.083 in)
13.916 mm
(0.5479 in)
14.048 mm
(0.5531 in)
-

-5Redistribution or publication of this document,
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SECTION 2. DIMENSIONS AND TORQUE
2-2 Generator Dimensions
2400 (2.0 kW)
Part
Main winding (R / Bu)
Field winding
Exciter winding (Bu / Bu)
DC winding (G / G)
Carbon brush
3500 (2.5 kW)
Part
Main windingⅠ(Br / W)
Main windingⅡ(R / Bu)
Field winding
Exciter winding (Bu / Bu)
DC winding (G / G)
Carbon brush

Item
Resistance
Resistance
Resistance
Resistance
Brush length

Factory specification
0.51-0.53 Ω
40-50 Ω
3.1-3.3 Ω
0.4-0.6 Ω
5-9 mm

Item
Resistance

Factory specification
0.76-0.79 Ω

Resistance
Resistance
Resistance
Resistance
Brush length

0.76-0.79 Ω
35-45 Ω
1.5-1.7 Ω
0.4-0.6 Ω
5-9 mm

2-3 Torque Specification
Part
Cylinder head bolt
Pivot bolt
Pivot adjusting nut
Crankcase cover bolt
Connecting rod bolt
Air cleaner wing nut
Air cleaner mounting nut
Muffler mounting bolt
Oil drain bolt
Fuel tank mounting bolt/ nut
Fuel valve joint nut
Oil level switch mounting nut
Flywheel mounting nut

Fastener size
8×1.25×55 mm
6×0.5 mm
6×1.25 mm
8×1.25×32 mm
7×1.25 mm
6×1.0 mm
6×1.0 mm
8×1.25 mm
10×1.5 mm
6×1.0 mm
10×1.25 mm
10×1.25 mm
14×1.25 mm

Torque values N· m (kg· cm, lb·ft)
26-28 (260-280, 18.8-20.2)
8-12 (80-120, 5.8-8.7)
22-26 (220-260, 15.9-18.8)
24-26 (240-260, 17.4-18.8)
12-14 (120-140, 8.7-17.4)
7-10 (70-100, 5.1-7.2)
7-10 (70-100, 5.1-7.2)
20-28 (200-280, 14.5-20.2)
20-25 (200-250, 14.5-18.1)
8-12 (80-120, 5.8-8.7)
20-25 (200-250, 14.5-18.1)
8-12 (80-120, 5.8-8.7)
80-90 (800-900, 58-865.3)

2-4 Standard Torques Specification

Standard torque values

5 mm bolt, nut
6 mm bolt, nut
8 mm bolt, nut
10 mm bolt, nut
12 mm bolt, nut

4-7 (40-70, 2.9-5.1)
8-12 (80-120, 5.8-8.7)
20-28 (200-280, 14.5-20.2)
35-40 (350-400, 14.5-20.2)
50-60 (500-600, 36.2-43.4)

-6Redistribution or publication of this document,
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SECTION 3. MAINTENANCE
3-1 Maintenance Schedule
Periodic maintenance is essential for top
performance. Use Table 3 as a guide. Under hot or
dusty operating conditions some maintenance
operations should be performed more frequently,
as indicated by the footnotes in the table.

Accidental starting of the generator
set during maintenance can cause severe
personal injury or death. Before performing
maintenance, disconnect the spark plug wire
from the spark plug.

Keep a log of maintenance performed and the
hours run. Recording maintenance will help you
keep it regular and provide a basis for supporting
warranty claims.

A hot generator set can cause
severe burns. Always allow the generator set
to cool before performing any maintenance or
service.

TABLE 3. PERIODIC MAINTENANCE SCHEDULE
SERVICE INTERVAL
SERVICE THESE ITEMS

EACH
USE

FIRST

MONTH OR MONTHS OR
20 HOURS

General Inspection

×1

Check Oil Level

Test GFCI

Change Engine Oil

EVERY 3

50 HOURS

EVERY

EVERY 6

EVERY

MONTH

MONTHS OR

YEAR OR

100 HOURS

300 HOURS

Clean Air Cleaner

×2

Clean Cylinder Cooling Fins

×2

Clean Spark Plug

Clean the Spark Arrestor

Clean Fuel Sediment Cup

×3

Clean Fuel Tank

×3

Adjust Valve Clearance

×3

Check fuel line

Every 2 years(Replace if necessary) 3

1.See GENERAL INSPECTIONS.
2.Service more frequently when used in dusty environments.
3. These items must be performed by a trained and experienced mechanic (authorized Onan dealer).
-7-

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SECTION 3. MAINTENANCE
3-2 Engine Oil

NOTE: Drain the oil while the engine is still
warm to assure rapid and complete draining.
1)

Remove the oil filler cap and drain plug.

Drain the oil from the crankcase.

Reinstall the oil filler cap and tighten it
securely.

RECOMMENDED ENGINE OIL:
SAE 10W-30 is recommended for general, all
temperature use: service classification
SG·SF/CC·CD.

20W-50
20W-40
Oil filler cap

10W-40

Oil drain bolt (M10)

Reinstall the drain plug securely.

Add new oil up to the bottom edge of the oil
filler hole with the engine stopped and in a level
position.

10W-30

Lower level

Used motor oil may cause skin
cancer if repeatedly left in contact with the skin
for prolonged periods. Thoroughly wash your
hands with soap and water as soon as possible
after handling used oil.

Engine Oil Capacity

1.16 US qt (1.1 L)
-8-

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SECTION 3. MAINTENANCE
3-3 Air Cleaner
A dirty air cleaner will restrict air flow
to the carburetor. To prevent carburetor
malfunction, service the air cleaner regularly.
Service more frequently when operating the
generator in extremely dusty areas.
Using gasoline or flammable
solvent to clean the filter element can cause a
fire or explosion. Use only soapy water or
nonflammable solvent.
AIR CLEANER COVER

Never run the generator without the
air cleaner. Rapid engine wear will result.
1)

CLIP

Remove the cleaner cover by unsnapping the
two spring clips. Clean more often in dusty
environments

2) Remove the two foam filter elements and
thoroughly wash them with soap and water. Let
them dry thoroughly.
3)

Knead in 1 teaspoon (5 cm3) of clean engine oil
into each foam filter element. The oil should be
distributed evenly throughout each filter
elements.

4) Reinstall the filter elements, the gray filter first
(finer pores) and then the black filter (larger
pores).
5)

Secure the cover with the spring clips.

AIR CLEANER ELEMENT

SOAP & WATER

ENGINE OIL

SQUEEZE

DRY

-9-

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SECTION 3. MAINTENANCE
3-5 Spark Arrester

3-4 Fuel Sediment Cup Cleaning
The sediment cup prevents dirt or water which may
be in the fuel tank from entering the carburetor. If
the engine has not been run for a long time, the
sediment cup should be cleaned.
1)
2)
3)
4)

A hot muffler can cause severe
burns. Allow the generator set to cool before
servicing the muffler.
Refer to MAINTENANCE SCHEDULE for
scheduled spark arrester cleaning. After letting the
generator set cool down, remove the spark arrester
screen. Inspect for damage, and replace if
defective. Clean any deposits on the screen with a
wire brush. Reinstall the spark arrester, and tighten
the screw securely.

Turn the fuel valve to the OFF position.
Remove the sediment cup, and o-ring.
Clean the sediment cup, and o-ring, in
nonflammable or high flash point solvent.
Reinstall o-ring, and sediment cup.
Turn the fuel valve ON and check for leaks.
FUEL VALVE

SEDIMENT CUP
(10 mm)

FUEL FILTER
O-RING

SEDIMENT CUP

Gasoline is extremely flammable
and is explosive. Do not smoke or allow flames
or sparks in the area.
After reassembly, check for leaks,
and make sure the area is dry before starting
the engine.

- 10 -

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SECTION 3. MAINTENANCE
7)

3-6 Spark Plug
To ensure proper engine operation, the spark plug
must be properly gapped and free of deposits.

If the engine has been running, the spark plug and
muffler will be very hot. Be careful not to touch the
muffler or spark plug.
1) Turn off generator.
2) Remove the spark plug cap.
3)
4)

If installing a new spark plug, tighten l/2 turn
after the spark plug seats to compress the
washer. If reinstalling a used spark plug, tighten
l/8 - l/4 turn after the spark plug seats to
compress the washer.

Clean any dirt from around the spark plug
base.
Use the wrench supplied in the tool kit to
remove the spark plug.
PLUG WRENCH

Check that the spark plug washer is in good
condition, and thread the spark plug in by hand
to prevent cross-threading.
After the spark plug is seated, tighten with a
spark plug wrench to compress the washer.

The spark plug must be securely
tightened. An improperly tightened spark plug
could damage the engine.

SPARK PLUG TORQUE
(20N•m-25N•m)

Never use spark plugs which have
an improper heat range. Use only the
recommended spark plugs or equivalent.

PLUG CAP

Visually inspect the spark plug. Discard it if the
insulator is cracked or chipped. Clean the
spark plug with a wire brush if it is to be reused.
Measure the plug gap with a feeler gauge.
Correct as necessary by carefully bending the
side electrode.

0.7-0.80mm

SIDE
ELECTRODE
METAL BRUSH

The gap should be: 0.70-0.80 mm (0.028-0.031 in).
- 11 -

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SECTION 3. MAINTENANCE
3-7 Valve Clearance
Valve clearance inspection and
adjustment must be performed with the engine
cold.
1) Remove the cylinder head cover, and set the
piston at top dead center of the compression
stroke (both valves fully closed). Pull the starter
until the piston is at top dead center of the
compression or exhaust stroke.
2) Insert a feeler gauge between the rocker arm
and valve to measure valve clearance.
Standard valve
clearance

IN.
EX.

0.10±0.02 mm
(0.004±0.001 in)
0.2±0.02 mm
(0.008±0.001 in)

3-8 Governor

ROCKER ARM

Take down the fuel tank.

Loosen the nut on the governor arm pinch bolt.

3) Move the arm until the throttle is completely
open, and hold it in that position.
4) Rotate the governor arm shaft as far as it will
go in same direction it was just moved by the
governor arm, and then tighten the governor arm
pinch bolt.

LOCK NUT
10N•m-140N•m

5) Whether check the arm and throttle move
smoothing.
6)

7) Start the engine and adjust the limiting screw to
produce the standard until the engine warm up to
normal operating temperature.

PIVOT
To increase valve clearance, screw lock nut out.
To decrease valve clearance, screw lock nut in.

Install the fuel tank.

Idle speed
GOVERNOR NUT
SPRING

If adjustment is necessary, proceed as follows:
a)

Hold the rocker arm pivot and loosen the
pivot lock nut.

Turn the rocker arm pivot to obtain the
specified clearance.

Retighten the lock nut while holding the
rocker arm pivot.

Recheck valve clearance after tightening
the lock nut.

3600±150rpm
GOVERNOR
ARM PINCH
BOLT

GOVERNOR
ARM SHAFT

nut
GOVERNOR ARM

THROTTLE
LIMITING SCREW

ANTI-SURGE SPRING

- 12 -

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SECTION 4. DISASSEMBLY AND SERVICE
ENGINE FLOODED too much fuel

4-1 Troubleshooting

(TRY AGAIN AFTER A FEW MINUTES)

4-1-1 Hard Starting
FUEL low
FUEL SYSTEM

(ADD FUEL INTO FUEL TANK)
FUEL FILTER clogged

(SEE 3-4)
CARBURETOR out of adjustment

(SEE 4-4-6)
AIR FILTER dirty

(SEE 3-3)
OIL low

(SEE 3-2)
SPARK PLUG GAP incorrect

(SEE 3-6)
SPARK PLUG CAP faulty

(SEE 4-4-2)
HARD
STARING

IGNITION
SYSTEM

IGNITION COIL GAP incorrect

(SEE 4-4-2)
IGNITION COIL faulty

(SEE 4-4-2)
START SWITCH faulty

(SEE 4-5-4)
OIL ALERT SYSTEM faulty

(SEE 4-4-1)
VALVE LASH incorrect

(SEE 3-7)
CYLINDER HEAD GASKET faulty

(SEE 4-4-3)
CYLINDER HEAD BOLT faulty

COMPRESSION
SYSTEM

(SEE 4-4-3)
VALVE faulty

(SEE 4-4-3)
CYLINDER / PISTON / PISTON RING worn

(SEE 4-4-1)
CAMSHAFT wore

(SEE 4-4-1)
- 13 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-1-2 Low Power
FUEL poor

(ADD CLEAN FRESH FUEL INTO TANK)
FUEL FILTER clogged

(SEE 3-4)

FUEL SYSTEM

CARBURETOR out of adjustment

(SEE 4-4-6)
CHOKE ROD not open

(MOVE TO “RUN” POSITION)
AIR FILTER dirty

(SEE 3-3)
SPARK PLUG faulty

IGNITION
SYSTEM

(SEE 3-6)
CAMSHAFT worn

(SEE 4-4-1)
CYLINDER / PISTON / PISTON RING worn

(SEE 4-4-1)
Low Power

COMPRESSION
SYSTEM

VALVE LASH out of Spec

(SEE 3-7)
VALVE SEAT worn or damaged

(SEE 4-4-3)
COOLING FAN dirty

(CLEAN)
COOLING CYLINDER FINS dirty

(CLEAN)
OTHER
MUFFLER clogged

(SEE 4-5-2)
GOVERNOR out of adjustment

(SEE 3-8)
ELECTRICAL LOADS too high

(REMOVE EXTRA LOADS)

- 14 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-1-3 Speed Unstable
FUEL low / poor quality / contaminated

(ADD NEW FUEL INTO FUEL TANK)
FUEL SYSTEM

FUEL FILTER clogged

(SEE 3-4)
CARBURETOR clogged

(SEE 4-4-6)

GOVERNOR out of adjustment
GOVERNOR
SYSTEM

(SEE 3-8)
ANTI-SURGE SPRING incorrect

(REPLACE)

SPEED
UNSTABLE

SPARK PLUG spark plug wire faulty
COMPRESSION
SYSTEM

(SEE 4-4-2)
CAMSHAFT worn

(SEE 4-4-1)

OIL low level
OTHER

(ADD NEW OIL)
ELECTRICAL LOADS too high

(REMOVE EXTRA LOADS)

- 15 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-1-4 Low Speed / Voltage

AIR FILTER dirty

(SEE 3-3)
FUEL poor / contaminated
FUEL SYSTEM

(ADD NEW FUEL)
CARBURETOR has water

(SEE 4-4-6)
CHOKE LEVER not open

(PUSH CHOKE ROD)

LOW
SPEED /
VOLTAGE

GOVERNOR out of adjustment
GOVERNOR
SYSTEM

(SEE 3-8)
ANTI-SURGE SPRING incorrect

(REPLACE)

MUFFLER clogged

(SEE 4-5-2)
OTHER

ALTERNATOR temperature is too high
(SEE 4-5-3)
(CLEAN ALTERNATOR FAN AND END
COVER)
ELECTRICAL LOADS too high

(REMOVE EXTRA LOADS)

- 16 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-1-5 Exhaust Color Abnormal

AIR FILTER dirty

(SEE3-3)
BLACK

CARBURETOR faulty

(SEE 4-4-6)

LOAD excessive

(REMOVE EXTRA LOAD)

ENGINE temperature is too low

EXHAUST
COLOR
ABNORMAL

(NORMAL WHEN STARTING)

WHITE

FUEL contaminated

(ADD FRESH FUEL)

FUEL contaminated with oil

(CHANGE TO FRESH FUEL)
CYLINDER / PISTON / PISTON RING worn
BLUE

(SEE 4-4-1)
OIL too much

(SEE 3-2)
BREATHER icing issue

(CLEAN BREATHER)

- 17 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-1-6 No AC Output Voltage

ENGINE SPEED abnormal

(CHECK IT AND ADJUST)

STATOR MAIN COIL defective

(SEE 4-5-3)

BRUSH defective

NO AC
OUTPUT
VOLTAGE

(SEE 4-5-3)

EXCITATION VOLTAGE too low

(SEE 4-5-3)

AVR defective

(SEE 4-5-3)

BREAKER tripped

(RESET BREAKERS)

4-1-7 No DC Output Voltage

BREAKER tripped

NO DC
OUTPUT
VOLTAGE

(RESET BREAKERS)

OTHER REASON

- 18 -

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SECTION 4. DISASSEMBLY AND SERVICE
TABLE 4-1 HAZARDS AND THEIR SOURCES

4-2 Preparing to Service

• Leaking or spilled fuel

4-2-1 Safety Considerations
There are hazards in servicing gensets. Study
Safety precautions and become familiar with the
hazards listed in table 4-1. Note the following
safeguards and ways of avoiding hazards.

Fire and
Explosion

• Oily rag improperly stored
• Flammable liquids improperly
stored

• Use personal protection: Wear appropriate
protective safety equipment, such as safety shoes
and safety glasses.

Burns

• Do not wear rings or jewelry and do not wear
loose or damp clothing that might get caught in
equipment or conduct electricity.

Poisonous
Gas

• Reduce the hazard: A safety, order workshop
area and well-maintained reduce the hazard
potential. Keep guards and shields in place on
machinery and maintain equipment in good working
condition. Store flammable liquids in approved
containers; away form fire, flame, spark, pilot light,
switches, arc-producing equipment and other
ignition sources. Keep the workshop clean and
well-lighted and provide adequate ventilation.
• Develop safe work habits: Unsafe actions cause
accidents with tools and machines. Be familiar with
the equipment and know how to use them safely.
Use the correct tool for the job and check its
condition before starting. Comply with the warnings
in this manual and take special precautions when
working around electrical equipment. Do not work
alone if possible and take no risks.
• Be prepared for an accident: Keep fire
extinguishers and safety equipment nearby.
Agencies such as the Red Cross and public safety
departments offer courses in first aid, CPR and fire
control. Take advantage of this information to be
ready to respond to an accident. Learn to be
safety-conscious and make safety procedures part
of the work routine.

• Hydrogen gas from battery

• Hot exhaust pipes
• Hot engine and generator surfaces
• Operating genset where exhaust
gases can accumulate
• Improper generator connections

Electrical
Shock (AC)

• Faulty wiring
• Working in damp conditions
• Jewelry touching electrical
components

Rotating
Machinery
Slippery
Surfaces

• Fan guards not in place
• Leaking or spilled oil

Heavy

• Removing genset form vehicle

Objects

• Removing heavy components

4-2-2 Special Tools
Engine
A complete set of standard and metric shop tools
are required to service the engine.
Control and Generator
A complete set of standard and metric shop tools
are required to service the control and generator.
Also needed are:
Lead or dead blow hammer
Battery hydrometer
Torque wrench
VOM millimeter
Frequency meter
Armature growler
Load bank
Jumper wires
Rotor Puller

- 19 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-3 Disassembly Chart
END COVER

MUFFLER

AVR
BRUSH

FUEL TANK
CONTROL BOX

MOUNT RUBBER

FRAME

REAR HOUSING

STATOR

ROTOR

ENGINE

CARBURATOR

AIR CLEANER

FLYWHEEL

STARTER MOTOR

FAN COVER

RECOIL STARTER

GENERATOR DISASSEMBLY

This chart is a quick-reference guide for
disassembling the product. Be sure to follow
the sequence shown here for better and safer
work.

Example:To remove the frame.
a) Remove the end cover.
b) Remove the control box.
c) Remove the fuel tank.
d) Remove the muffler.
e) Remove the frame.
- 20 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-4 Engine
4-4-1 Crankshaft / piston
a.DISASSEMBLY/ ASSEMBLY

Crankshaft
REASSEMBLY:
Check that the decompressor
weight moves smoothly, and
the spring is not weak or worn.

PISTON
REASSEMBLY:
Install with the
triangle mark
toward the push
rods.

DECOMPRESSOR
WEIGHT

VALVE LIFTER
REASSEMBLY:
Install the tappets
immediately
before installing
the camshaft.

OIL LEVER SWITCH

OIL ALERT UNIT
CONNECTING ROD CAP
REASSEMBLY:
Install with the oil dipper
toward the camshaft .
The ribs on the cap and
connecting rod must be
aligned.

CRANKSHAFT
REASSEMBLY:
Push in until the bearing
touches the crankcase. Be
careful not to damage the oil
seal.
- 21 -

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SECTION 4. DISASSEMBLY AND SERVICE
b.PISTON/ PISTON RING
PISTON RING
REASSEMBLY:
1) Install all rings with the markings facing upward.
2) Be sure that the top (chrome plated) and second rings are not interchanged.
3) Check that the rings rotate smoothly after installation.
4) Space the piston ring end gaps 120 degrees apart, and do not align the gaps with the
piston pin bore.

TOP RING
(CHROME PLATED)

OIL RING

MARKING
SECOND RING
PISTON

PISTON PIN

PISTON PIN CLIP
REASSEMBLY:
Install by setting one end of the clip
in the piston groove, holding the
other end with long-nosed pliers,
and rotating the clip in. Do not align
the end gap of the clip with the
cut-out in the piston pin bore.

PISTON PIN
REASSEMBLY:
Install the connecting rod
with the long end toward the
triangle marked side of the
piston.

- 22 -

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SECTION 4. DISASSEMBLY AND SERVICE
c.CAMSHAFT/ CRANKSHAFT

d.OIL LEVEL SWITCH
Ckeck continuity of the switch with an ohmmeter.

REASSEMBLY:
Align the index marks on the
camshaft and timing gear.

1) Hold the switch in its normal position. The
ohmmeter should read zero resistance.
2) Hold the switch upside down. The ohmmeter
should read infinity (∞) resistance.

CRANKSHAFT
INDEX MARKS

CAMSHAFT

3) Inspect the float by dipping the switch into a
container of oil. The ohmmeter reading should
go from zero to infinty as the switch is lowered.

CRANKSHAFT

(OFF)

(ON)

- 23 -

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SECTION 4. DISASSEMBLY AND SERVICE
d.INSPECTION

PISTON RING SIDE CLEARANCE
Factory
Allowable limit
Specification
0.030-0.060 mm
0.15 mm
(0.0012-0.0024 in)
(0.006 in)

CYLINDER ID(Inside Diameter)
Factory Specification
Allowable limit
68.015 mm
68.165 mm
(2.6778 in)
(2.684 in)

PISTON RING END GAP
Factory
Allowable limit
Specification
0.2-0.4 mm
1.0 mm
(0.008-0.016 in)
(0.04 in)

PISTON SKIRT OD(Outside Diameter)
Factory Specification
Allowable limit
67.985 mm
67.845 mm
(2.6766 in)
(2.6711 in)
PISTON-TO CYLINDER CLEARANCE
Factory Specification
Allowable limit
0.03-0.05 mm
0.12 mm
(0.0012-0.002 in)
(0.005 in)

PISTON PIN OD
Factory
Specification
17.998 mm
(0.7086 in)

Allowable limit
17.954 mm
(0.7068 in)

- 24 -

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SECTION 4. DISASSEMBLY AND SERVICE

CONNECTING ROD BIG END ID
Factory
Allowable limit
Specification
30.015 mm
30.066 mm
(1.1817 in)
(1.1837 in)
PISTON PIN BORE ID
Factory
Allowable limit
Specification
18.002 mm
18.048 mm
(0.7087 in)
(0.7105 in)
PISTON-TO-PISTON PIN BORE CLEARANCE
Factory
Allowable limit
Specification
0.004.016 mm
0.08 mm
(0.00016-0.0006 in)
(0.0.003 in)

CONNECTING ROD SMALL END ID
Factory
Allowable limit
Specification
18.006 mm
18.07 mm
(0.7089 in)
(0.711 in)

CRANKPIN OD
Factory
Specification
29.985 mm
(1.181 in)

Allowable limit
29.92 mm
(1.178 in)

CONNECTING ROD BIG END SIDE CLEARANCE
Factory
Allowable limit
Specification
0.1-0.7 mm
1.1 mm
(0.0040.028 in)
(0.043 in)
- 25 -

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SECTION 4. DISASSEMBLY AND SERVICE

CAMSHAFT DIAMETER
Factory
Specification
IN
27.7 mm (1.09in)
EX

27.75 mm
(1.093 in)

Allowable limit
27.45 mm
(1.081 in)
27.50mm
(1.083 in)

CAMSHAFT HOLDER ID
Factory
Specification
14.00 mm
(0.55 in)

Allowable limit
16.048 mm
(0.5531 in)

CAMSHAFT CAM DIAMETER
Factory
Allowable limit
Specification
13.916 mm
13.984 mm
(0.5506 in)
(0.5479 in)

- 26 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-4-2 Flywheel
a.DISASSEMBLY/ ASSEMBLY

SPARK PLUG LEAD
REASSEMBLY:
Clamp securely to the crankcase
with the two clamps.

WOODRUFF KEY
REASSEMBLY:
After installing the flywheel, check
to be sure that the woodruff key is
still in its slot on the crankshaft.

SPARK PLUG LEAD
REASSEMBLY:
Check for cracked or damaged
insulation; replace if necessary.

- 27 -

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SECTION 4. DISASSEMBLY AND SERVICE
b. INSPECTION

IGNITION COIL RESISTANCE
Primary side resistance value

IGNITION COIL

0.8-1.0 Ω

Secondary side resistance value
1.

Measure the resistance of the primary coil by
attaching one ohm-meter lead to the ignition
coil’s primary lead while touching the other test
lead to the iron core.

Measure the resistance of the secondary side
of the coil by removing the spark plug cap and
touching one test lead to the spark plug lead
wire while touching the other test lead to the
iron core.

0.4± 0.2 mm
(0.016± 0.008 in)

FLYWHEEL

AIR GAP (AT FLYWHEEL)
Measure the air gap between of the ignition and
flywheel by thickness gauge.
Air gap
(at flywheel)

5.9-7.1 KΩ

NOTE: A false reading will result if the spark plug
cap is not removed.
If the resistance is not as specified, replace the
ignition coil.

0.4±0.2 mm
(0.016±0.008 in)

SPARK PLUG CAP
Measure the resistance of the spark plug cap by
attaching one ohm-meter.
If the resistance is not as specified, change the
spark plug cap.
Spark Plug Cap

- 28 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-4-3 Cylinder Head / Valves
a.DISASSEMBLY/ ASSEMBLY
CYLINDER HEAD

REASSEMBLY:
Before installation, remove carbon deposits from
the combustion chamber and inspect the valve
seats.
Measure the compression of the cylinder head
after reassembly.

CYLINDER HEAD GASKET

CYLINDER
HEAD BOLT
CYLINDER HEAD
COVER

CYLINDER HEAD
COVER GASKET

CRANKCASE

CYLINDER HEAD COVER BOLT

CYLINDER HEAD BOLT

CYLINDER HEAD COVER BOLT

TORQUE:

26-28 N· m (260-280 kg· cm, 18.7-20.2 ft· lb)

12-14 N· m (120-140 kg· cm, 8.7-17.4 ft· lb)

REASSEMBLY/ DISASSEMBLY:

Tighten and untighten using a cross pattern.

Tighten and untighen using a cross pattern.

- 29 -

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SECTION 4. DISASSEMBLY AND SERVICE
ROCKER ARM

SPARK PLUG

EXHAUST VALVE

REASSEMBLY:

Check the pivot bolt,
push rod and rocker
arm before installing.

Before installation, clean
and adjust the spark plug.

Check both ends for
wear and check the
rod for straightness.
Be sure the rod ends
are firmly seated in the
lifter.

VALVE ROTATOR

REASSEMBLY:
If the valve
rotator is not installed, the
valve may drop into the
cylinder when starting the
engine.

PUSH ROD

REASSEMBLY:
Before installation, remove
carbon deposits and inspect
the valve.
INTAKE VALVE

Do not remove the valve spring
retainers while the cylinder head is installed, or
the valves will drop into the cylinder.

VALVE HEAD
DIAMETER:
IN: 24 mm

DISASSEMBLY:

(0.94 in)

Compress the value spring and slide the retainer
out to the side, so the valve stem slips through
the hole at the side of the retainer.

REASSEMBLY:
Do not interchange
with the exhaust valve.

EX: 22 mm
(0.87 in)

- 30 -

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SECTION 4. DISASSEMBLY AND SERVICE
b.INSPECTION
STRAIGHT EDGE

FEELER GAUGE

CYLINDER HEAD
Remove carbon deposits from the combustion
chamber. Clean off any gasket material from the
cylinder head surface.
Check the spark plug hole and valve areas for
cracks.
Check the cylinder head for warpage with a straight
edge and a feeler gauge.
Allowable limit

0.1 mm (0.004 in)

GUIDE TO STEM CLEARANCE
Subtract each valve stem O.D. from the
corresponding guide I.D. to the stem to guide
clearance.
Factory
Allowable limit
Specification
0.10 mm
0.02-0.044 mm
IN
(0.0008-0.0016 in)
(0.004 in)
0.12 mm
0.06-0.087 mm
EX
(0.0002-0.0034 in)
(0.005 in)

VALVE SEAT WIDTH
Measure the valve seat width.
If the valve seat width is under the factory section,
or over the service limit, recondition the valve seat.
Factory
Specification

Allowable limit

0.8 mm (0.03 in)

2.0 mm (0.08 in)

VALVE GUIDE ID
NOTE: Ream the valve guides to remove any
carbon deposits before measuring.
Measure and record each valve guide I. D.
Factory Specification
Allowable limit
5.50 mm (0.217 in)
5.572 mm (0.2193 in)
Replace the cylinder header if they are over the
allowable limit.

If the stem to guide clearance exceeds the
Allowable limit, determine if the new guide with
standard dimensions would bring the clearance
within tolerance. If so, replace any guide as
necessary and ream to fit. If the stem to guide
clearance exceeds the allowable limit with new
guides, replace the valves as well.
NOTE: Recondition the valve seats whenever the
valve guides are replaced.

- 31 -

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SECTION 4. DISASSEMBLY AND SERVICE

VALVE STEM OD
Inspect each valve for face irregularities, bending or
abnormal stem wear. Replace the valve if
necessary. Measure and record each valve stem
O.D.
Factory
Allowable limit
Specification
IN
5.318 mm
5.48 mm (0.216 in)
(0.2093 in)
EX
5.275 mm
5.44 mm (0.214 in)
(0.2077 in)
Replace the valves if their O.D. is smaller than the
allowable limit.

VALVE SPRING FREE LENGTH
Measure the free length of the valve springs.
Factory
Specification

Allowable limit

30.0 mm (1.18 in)

28.5 mm (1.122 in)

Replace the springs if they are shorter than the
allowable limit.

- 32 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-4-4 Recoil Starter / Fan Cover
a.DISASSEMBLY/ ASSEMBLY

FLANGE NUT 16mm

STARTER PULLEY

DISASSEMBLY/ REASSEMBLY:
REASSEMBLY:
Install by aligning the hole in the
pulley with the lug on the cooling
fan.

Hold the flywheel by placing a
screwdriver into the pulley.

FAN COVER

DISASSEMBLY/ REASSEMBLY:
Remove and install with the recoil
starter ASSY.

COOLING FAN

REASSEMBLY:

RECOIL STARTER ASSY

Install by aligning the three lugs on the rear
side of the fan with the small hole in the
flywheel.

REASSEMBLY:
Install with the starter grip position
as shown.

When disassembling and assembling, take
care not to damage the fan blades.

- 33 -

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SECTION 4. DISASSEMBLY AND SERVICE
b.DISASSEMBLY (RECOIL STARTER ASSY)
The recoil starter can cause personal injury, Wear safety glasses. Do not let the recoil spring
snap.

REEL COVER

REASSEMBLY:
Align the ratchet with the reel cover
notch.

STARTER REEL

REASSEMBLY:
Install on the starter case after
installing the return spring.

RATCHET

REASSEMBLY:
Check for wear or damage.
Note the installation direction.

RETURN SPRING

REASSEMBLY:
Hook the outer hook in the groove
of the starter reel and inner hook on
the starter case tab.

STARTER ROE

REASSEMBLY:
Install with the starter grip position
as shown.

- 34 -

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SECTION 4. DISASSEMBLY AND SERVICE
c.RECOIL STARTER ASSEMBLY

With a short length of the rope extending from
the starter reel notch, pull the end of the rope
out of the case, feed it through the starter grip,
and tie a knot in the end of the rope.

Install the friction plates, friction spring, ratchet
pin, guide plate, and reel cover. Tighten the
reel cover bolt.

Rotate the reel three full turns in the direction of
the arrow.

Check the operation of the ratchet by pulling
the starter rope out several times.

Wear gloves and eye wear to protect
your hands and eyes.
Do not let the return spring jump.

Hook the spring outer hook in the reel groove,
and install the reel on the starter case, so that
the spring inner hook is hooked to the starter
case tab by turning the reel counterclockwise.

Feed the end of the rope through the hole in
the starter reel, and tie the rope end. Wind the
rope onto the direction shown, and wedge the
rope end in the notch on the edge of the reel.

- 35 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-4-5 Air Cleaner
DISASSEMBLLY/ REASSEMBLY
BREATHER TUBE

REASSEMBLY:
Connect between the air cleaner
case and tappet cover.

SEAL
ELEMENT

AIR CLEANER CASE
AIR CLEANER GASKET

REASSEMBLY:

SEPARATOR

Make sure the gasket is not
damaged, broken or bent. Install
correctly as shown.

AIR CLEANER COVER

REASSEMBLY:
Make sure to seat the gasket in the
groove on the edge of the case all
the way around properly.

- 36 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-4-6 Carburetor
DISASSEMBLLY/ REASSEMBLY
Gasoline is flammable and explosive. Close the fuel shut off valve, and drain the carburetor
before servicing the carburetor.

PILOT SCREW
CARBURETOR BODY

REASSEMBLY:

Check the screw head
for wear or damage
before installing. INITIAL
OPENING: 1-5/8 turns
out.

Clean internal passages and
orifices with compressed air before
installing.
O-RING

MAIN JET

REASSEMBLY:

Check for correct installation.

Clean thoroughly with

MAIN NOZZLE

compressed air before
REASSEMBLY:

installation.

Clean thoroughly with
compressed air before
FLOAT

installation.

REASSEMBLY:
FLOAT VALVE

Check for smooth movement
after installing.

REASSEMBLY:

SET BOLT

Check for worn valve or
weak spring before
installation.

REASSEMBLY:

DRAIN SCREW

After assembly, check for
any sign of fuel leakage.

REASSEMBLY:
Clean thoroughly with
compressed air and check
for leaks after installation.

- 37 -

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SECTION 4. DISASSEMBLY AND SERVICE
4-5 Generator
4-5-1 Fuel Tank
DISASSEMBLLY/ REASSEMBLY
Gasoline is flammable and explosive. Drain the fuel tank and fuel line before disassembly.
Wipe up spilled fuel immediately.
FUEL TANK CAP

REASSEMBLY:
Make sure that the air vent
hole is clean and
unclogged. Blow with
compressed air if
necessary.

FUEL METER

REASSEMBLY:
After reassembly, check
the operation of the float.

FUEL STRAINER

REASSEMBLY:
Check to be sure the
strainer is clean and
undamaged before
installation.

FUEL TANK
FUEL VALVE

REASSEMBLY:

Wash the tank to
remove sediment,

Make sure the passages
are not clogged.
Check for fuel leakage
after installation.
FUEL FILTER
SEDIMENT CUP

REASSEMBLY:
REASSEMBLY:

Check to be sure the filter is
clean and undamaged.

Wash to remove sediment.
and dry thoroughly before
installation.

- 38 -

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by any means, is strictly prohibited.

SECTION 4. DISASSEMBLY AND SERVICE
4-5-2 Muffler
DISASSEMBLLY/ REASSEMBLY
EXHAUST PIPE

REASSEMBLY:
Install after removing the
carbon deposits from the
exhaust pipe.

EXHAUST PIPE

REASSEMBLY:
Attach after removing the
carbon from the screen with a
wire brush.

MUFFLER

REASSEMBLY:
Install after removing
the carbon deposits
from the muffler using
a plastic hammer.

- 39 -

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by any means, is strictly prohibited.

SECTION 4. DISASSEMBLY AND SERVICE
4-5-3 Generator
CRANKCASE GROMMET

a. DISASSEMBLLY/ REASSEMBLY
GENERATOR ASSY

REASSEMBLY:
REASSEMBLY:

Check to be sure the grommet
is inserted securely.

Wipe dirt or oil off the tapered
portion of the rotor and
crankshaft before installing.
BRUSH HOLDER ASSY

DISASSEMBLY:
Remove the brush holder
before the rotor and stator.

ROTOR BOLT

REASSEMBLY:
43-47 N·m (430-470 kg·cm,
31.0-33.9 ft·lb)

STATOR BOLT

REASSEMBLY:
Tighten in crisscross pattern
in 2-3 steps.
After tightening, make sure
there is no clearance
between the crankcase
cover and stator cover.
8-12 N·m (80-120 kg·cm,
5.8-8.7 ft·lb)
RUBBER MOUNT

REASSEMBLY:
Insert the alignment tabs onto the holes.
Make sure the rubber is not chipped, hard or worn.
Note the installation direction.
- 40 -

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by any means, is strictly prohibited.

SECTION 4. DISASSEMBLY AND SERVICE
REAR HOUSING
REAR HOUSING

BRUSH HOLDER ASSY

AVR ASSY
AC OUTPUT TERMINAL

GENERATOR
COOLING FAN
GENERATOR END COVER
STATOR COVER
STATOR

ROTOR

DISASSEMBLY:
Install the appropriate rotor puller (special tool), hold the
flywheel and torque the puller to 6.9 Kg-cm (50 ft-lb).
To avoid damaging the rotor, place a wooden
block and a shop rag under the rotor for support.
NOTE:
If torquing the rotor puller does not free the rotor from the
crankshaft, tap the end of the puller with a brass hammer to
help loosen the rotor.
To prevent eye injury, always wear safety
glasses or goggles when striking the end of the rotor puller.

- 41 -

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by any means, is strictly prohibited.

SECTION 4. DISASSEMBLY AND SERVICE
b. INSPECTION

CARBON BRUSH/ SLIP RING

FIELD WINDING

Remove the carbon brushes from the brush holder.

Remove the brushes and measure resistance
between the slip rings.

Check the brush for length, wearing condition or
any other defect. Replace if the length is less than
5 mm (0.20in).

RESISTANCE

NOTE:
z

Connect the Blue wire lead to the positive (+)
side of the brush holder.

Avoid damaging the brushes when removing
and installing the brush holder.

Visually inspect the slip rings for dust, rust or other
damage. If necessary, wipe them with a clean
lint-free cloth. If they are rusted or damaged,
remove the rotor and rub with fine emery cloth.

2400

40-50 Ω

2500

35-45 Ω

If the specified resistance is obtained at the slip
rings, but not at the brush terminals, clean or
replace the brushes.
If the specified resistance is not obtained at the slip
rings, clean or replace the rotor.

- 42 -

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by any means, is strictly prohibited.

SECTION 4. DISASSEMBLY AND SERVICE
AC OUTPUT
TERMINALS

Br
Br
W
W
EXCITER WINDING
2400

Using an ohmmeter, measure the resistance
between the Light green/ Red and Green wires in
the 4P coupler.
AC OUTPUT
TERMINALS
RESISTANCE

Br
W
R

Br
(Ⅰ)
W

2400

3.1-3.3 Ω

3500

1..5-1.7 Ω

Slip ring Ground

∝

If the resistance is zero or infinity, replace the stator.

(Ⅱ)
Bu
3500
MAIN WINDING
Using an ohmmeter, measure the resistance
between the AC output terminals.
2400

0.51-0.53 Ω
DC WINDING

RESISTANCE 3500（Ⅰ） 0.76-0.79 Ω

Using an ohmmeter, measure the resistance
between the brown wire leads at the DC diode
connecter.

3500（Ⅱ） 0.76-0.79Ω

NOTE:

RESISTANCE

Set the voltage selector switch to 120 V only
position.
If the resistance is zero or infinity, replace the stator.

0.4-0.6 Ω

If the resistance is out of specification, replace the
stator.

- 43 -

Redistribution or publication of this document,
by any means, is strictly prohibited.

SECTION 4. DISASSEMBLY AND SERVICE
4-5-4 Control Panel
a. DISASSEMBLLY/ REASSEMBLY
GENERATOR END COVER

CONTROL PANEL

- 44 -

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by any means, is strictly prohibited.

SECTION 4. DISASSEMBLY AND SERVICE
2400

PANEL END COVER

DC BREAKER
RESET SWITCH

AC BREAKER
RESET SWITCHES

GFCI
VOLTMETER

EARTH
GROUND
LUG

ON/STOP
SWITCH

12 Volt DC
Terminals
PANEL FRONT COVER

- 45 -

Redistribution or publication of this document,
by any means, is strictly prohibited.

SECTION 4. DISASSEMBLY AND SERVICE
3500
PANEL END COVER

FUSE AND FUSE COVER

DC BREAKER
RESET SWITCH

VOLTAGE
SELECTOR WITCH

AC BREAKER
RESET SWITCHES

AC BREAKER
RESET SWITCH

VOLTMETER

AC RECEPTACLE
(120/240VAC)
EARTH
GROUND
LUG

START/ON/STOP
SWITCH

GFCI

12 Volt DC
Terminals

PANEL FRONT COVER

- 46 -

Redistribution or publication of this document,
by any means, is strictly prohibited.

SECTION 4. DISASSEMBLY AND SERVICE
2400

DC DIODE 4P COUPLER
1) Red (+)
2) Blue (-)
Blue (+)
Yellow (-)
GROUND CABLE
AC OUTPUT
TERMINAL STRIP

Brown
White
Brown
White

AVR

EXCITER WINDING 4P COUPLER
3) Blue
4) Green
5) White

- 47 -

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by any means, is strictly prohibited.

SECTION 4. DISASSEMBLY AND SERVICE
3500
DC DIODE 4P COUPLER
1) Red (+)
2) Blue (-)
Yellow (-)
Blue (+)
GROUND CABLE
AC OUTPUT
TERMINAL STRIP

Brown

Main Winding(Ⅰ)
White

White

Red

Red
Main Winding(Ⅱ)

Blue

EXCITER WINDING 4P COUPLER
3) Blue
4) Green
5) White

AVR

- 48 -

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by any means, is strictly prohibited.

SECTION 4. DISASSEMBLY AND SERVICE
b. INSPECTION

AC BREAKER RESET SWITCHES

ENGINE SWITCH

Check continuity between the breaker terminals.
There should be continuity with the breaker button
pushed in.

Check for continuity between the terminals with the
switch in each position.
L

VOLTMETER

ST
BAT

Using an ohmmeter, check for continuity between
the terminals.

Continuity should exist between them.
Wire

Position

Yellow/
Black

Black

Green/
White

Red

White

OFF
ON
When switch to “OFF” position, IG is connecting to
E. When switch to “ON” position, L is connecting to
L.

AC RECEPTACLE
Connect the terminals of the receptacles with a
piece of wire.

Check continuity between the breaker terminals.

Using an ohmmeter, check for continuity between
the terminals.

There should be continuity with the breaker button
pushed in.

If there is no continuity, the receptacle is defective,
and must be replaced.

DC BREAKER RESET SWITCH

- 49 -

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by any means, is strictly prohibited.

SECTION 5. WIRING DIAGRAMS
5-1 The Wiring Diagram of 2400

+
0

100

V
~
200

300

OFF

Bu Blue

Red

Green

White

Lg Light green

Yellow

Black

Brown

IG E

- 50 -

Redistribution or publication of this document,
by any means, is strictly prohibited.

SECTION 5. WIRING DIAGRAMS
5-2 The Wiring Diagram of 3500

+
-

OFF

Blue

Red

Green

White

Lg Light green

Yellow

Black

Brown

IG E

- 51 -

Redistribution or publication of this document,
by any means, is strictly prohibited.

Cummins Power Generation
1400 73rd Avenue N.E.
Minneapolis, MN 55432
763–574–5000
Fax: 763–528–7229
Cummins and Onan are registered trademarks of Cummins Inc.

Redistribution or publication of this document,
by any means, is strictly prohibited.

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