AHS2510 Shin Service Bulletin
User Manual: AHS2510
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SHINDAIWA TECHNICAL INFORMATION
March 17, 2009
Models affected:
All C4 models
T2510
T3410
T2510X
C3410
C2510
CT2510
T3410X
EB2510
EB3410
GP3410
M2510
DH2510
HT2510
AH2510
AHS2510
LE2510
PB3410
EB8510
EB8520
Note:
Technical Service
Bulletin
No: TSB-299
C4 Unit Valve
Adjustment
Details: The Importance of proper maintenance on C4 Units
Shindaiwa, Inc.
11975 S.W. Herman Road
Tualatin, Oregon 97062
Telephone 503.692.3070
Fax 503.692.6696
www.shindaiwa.com
See TSB 289 for valve adjustment tools. Video clip instructions are located under the
Technical Information link in “Training Videos” of the Shindaiwa Dealer Website
The original T2500 trimmer was introduced in 2001. We now have over 7 years of
eld experience with C4 units from T2510 thru EB8510. From that experience, we’ve
learned, like the motorcycle industry when they moved from 2-stroke to 4-stroke; air lter
maintenance is the single most critical element. More than one distributor salesman has
stated it bluntly to potential customers: “If you are not willing to do a minimal level of air
lter maintenance, perhaps 4-stroke is NOT for you”!
A 4-stroke engine contains more moving parts; parts that are also more heavily loaded
in a concentrated area (example: pushrod ends, rocker arms, followers). Any ingestion
of debris inside the engine can create rapid wear on these components. The end result:
excessive valve lash and the need for more frequent valve adjustment.
Although the valve adjustment is recommended at 139 hours, Engineering test
results have shown a C4 engine can go as long as 700 hours or more between valve
adjustments if (and only if) air lter and the lter system are properly maintained.
Air lter inspection should be performed on a daily basis for commercial units.
Proper air lter maintenance* includes daily inspection of all air lter components for
damage, wear, or excessive movement. Any of these three can allow debris to bypass
the air lter.
When to adjust? Rather than try to track actual hours on a C4 unit, we’ve seen this to be
a very good rule of thumb: If the engine cranks over and starts easily, leave it alone. If
hard to start, valve lash is worth checking. For 2510/3410 units, the combination of hard
to start and hard to crank is the primary indication of the need to adjust valves. As valve
lash increases, the decompression lobe eventually does not contact the cam and the
recoil cord becomes signicantly harder to pull.
In the past, and on a limited basis, we’ve offered to provide the rst valve
adjustment for C4 units. Today, to continue that program invites a lower level
of air lter maintenance and so is ofcially discontinued.
* Our strong recommendation is to make air lter maintenance a major part of the
predelivery discussion with customers. Perhaps adding a prelter or two at time of
purchase will help instill the importance of this critical task.
2510/3410 Series
Valve Clearance:
0.004”
8510/8520 Series
Valve Clearance:
0.002”
