92
MS 271 C, MS 291 C
12.7.2 Standard setting
The limiter cap (1) must not be
removed for the standard setting.
Always perform the following steps
before carrying out any
adjustments:
– Troubleshooting,
– Check chain tension and adjust if
necessary.
– Inspect the spark arresting
screen (if fitted) and clean or
replace if necessary,
b
6.1
– Check the air filter and clean or
replace if necessary,
b
12.1
Standard setting
– Shut off the engine.
– Turn the high speed screw (
H
)
slowly counterclockwise as far as
stop, but not more than
a 3/4 turn.
– Turn the low speed screw (
L
)
slowly clockwise as far as stop,
then turn it back
1 full turn.
5902RA394 TG
1
Check running behavior:
The engine must idle and
accelerate smoothly.
Adjusting engine idle speed
– Carry out standard setting.
– Warm up the engine.
Engine stops while idling
– Turn the idle speed screw (
LA
clockwise until the chain starts
running, then turn it back 1 full
turn.
Saw chain runs while engine is
idling
– Turn the idle speed screw (
LA
)
counterclockwise until the chain
stops running, then turn it back
one full turn.
Erratic idling behavior, poor
acceleration
(although standard setting is
correct)
Idle setting too lean.
– Warm up the engine.
– Turn the low speed screw (L )
counterclockwise until the engine
runs and accelerates smoothly.
It is usually necessary to change the
setting of the idle speed screw (
LA
)
after every correction to the low
speed screw (
L
).
Adjustment for operation at high
altitude
A minor correction may be
necessary if engine power is not
satisfactory when operating at high
altitude.
– Check standard setting.
– Warm up the engine.
– Turn the high speed screw (
H
)
clockwise (leaner) – no further
than stop.
Turn the adjusting screws only very
slightly. Even minor adjustments
can noticeably affect engine running
behavior.
If the setting is made too lean there
is a risk of engine damage as a
result of lack of lubrication and
overheating.
12.8
Carburetor Carrier
– Remove the carburetor,
b
12.5
:
Remove the shim (1).
2710RA281 TG
1
