Engine Management; Adjusting The Carburetor - Stihl MS 231 Instruction Manual

English

Engine Management

Exhaust emissions are controlled by the
design of the engine and components
(e.g. carburation, ignition, timing and
valve or port timing).
36

Adjusting the Carburetor

Basic information
The carburetor comes from the factory
with a standard setting.
The carburetor has been adjusted for
optimum performance and fuel
efficiency in all operating states.
Standard setting
Switch off the engine
N
Check the air filter – clean or replace
N
it if necessary
Turn the high speed adjusting
N
screw (H) counterclockwise as far
as possible (max. 3/4 turn)
Turn the low speed adjusting
N
screw (L) clockwise until it is firmly
in its seat – then back off 1/4 turn
Setting the idle speed
Make standard setting
N
Start engine and let it warm up
N
Engine stops when idling
Turn the idle speed adjusting screw
N
(LA) clockwise until the saw chain
begins to run – then turn it back
2 3/4 turn.
Saw chain rotates at idle speed
Turn the idle speed screw (LA)
N
counterclockwise until the saw
chain stops turning – then turn
another 2 3/4 turns in the same
direction
WARNING
If the saw chain continues to keep
rotating in idle even after adjustment,
have the chain saw checked by a
servicing dealer.
Speed erratic when idling; poor
acceleration (despite standard setting of
low speed adjusting screw)
The idle setting is too lean.
Carefully turn the low speed
N
adjusting screw (L)
counterclockwise until the engine
runs smoothly and accelerates
properly.
MS 231, MS 231 C, MS 251, MS 251 C