Shindaiwa AHS2510/EVC Owner's/Operator's Manual page 16

Maintenance (continued)
139/150-Hour Maintenance
Maintenance after first 139-hours,
then ever y 150-hours thereafter.
Combustion chamber should be decar-
bonized, and the valve clearance should
be adjusted. It is highly recommended
that this is done by a Shindaiwa-trained
service technician.
Valve Adjustment
1. Remove cylinder cover, rocker arm cover,
and spark plug. Rotate the crankshaft
while observing the piston through the
spark plug opening. When the piston
is at the top of the compression stroke
(TDC), the valves can be adjusted.
CAUTION!
Performing a valve adjustment
incorrectly may cause hard starting
and/or can damage the engine.
If you are unfamiliar with this
engine or uncomfortable with this
procedure, consult with an autho-
rized Shindaiwa servicing dealer.
Cutter blade adjustment
WARNING!
The cutter blades are very
sharp! Always wear gloves when work-
ing around the cutter assembly.
Cutting performance of your machine
depends a great deal on proper cutter blade
adjustment. Properly adjusted blades will
oscillate freely yet help prevent binding of
cut material between blades. Adjust blades
as follows:
1. Loosen all blade locknuts at least one
full turn.
2. Tighten each blade shoulder bolt
firmly, and then loosen the shoulder
bolts 1/4 to 1/2 turn.
16
Replace the spark plug annually: Use
only the type recommended in the
"Specifications" section or an equivalent
resistor type spark plug of the correct
heat range. Set spark plug electrode
gap to 0.6 -0.7 mm.
2. Loosen adjuster locknut so that the
2.5 mm Allen socket head adjustment
screw can turn freely.
3. Insert 0.10 mm feeler gauge between
valve stem tip and rocker arm.
4. Turn adjustment screw (clockwise =
tighter, counter-clockwise = looser)
until feeler gauge is almost snug. Back
off just enough to allow gauge to slip
out with limited resistance.
5. While holding the adjustment screw in
place with the Allen driver, tighten the
locknut with a wrench.
3. Working from the gearcase end, lock
each bolt in place by firmly tightening
its locknut while preventing the shoul-
der bolt from turning.
When shoulder bolt adjustment is cor-
rect, there should be a gap of 0.25–0.50
mm between the cutter blades and the flat
washers, and the flat washer beneath each
bolt head should turn freely.
CAUTION!
Operating the trimmer with worn or
improperly adjusted cutters will reduce
cutter performance and may also dam-
age your machine. Never operate the
machine with damaged or worn cutters.
The valve clearance should be adjusted
annually or every 135 hours. It is
highly recommended that this is
done by a Shindaiwa-trained service
technician.
6. Turn engine over several times, and
returnthe to TDC-compression.
Recheck with proper feeler gauge to
make sure clearance adjustment did
not change as a result of tightening the
locknut. Readjust as necessary.
7. Replace rocker arm cover gasket to
assure proper sealing and install cover.
IMPORTANT!
If a new gasket is not available and/or the
old gasket is not damaged, the old gasket
may be reused. Never use cracked or dam-
aged gaskets!
Guide Bar
Cutter
Blades
Shoulder Bolt
Adjusting cutter blades
Locknut
Washer (should
turn freely)