Adjusting The Carburetor - Stihl SR 440 Instruction Manual

18 Adjusting the Carburetor

17.1 If there is a noticeable loss of
engine power
► Turn the choke knob to c .
► Loosen the screws (1).
► Remove the filter cover (2).
3
► Remove the filter element (3).
► Replace dirty or damaged filters.
► Fit the new filter in the filter housing.
► Fit the filter cover.
► Fit the screws and tighten them down firmly.
18 Adjusting the Carburetor
18.1 General Information
The carburetor comes from the factory with a
standard setting.
This setting provides an optimum fuel-air mixture
under most operating conditions.
0458-450-8721-C
1
2
1
18.2 Preparations
► Shut off the engine.
► Check the air filter and clean or replace if nec‐
essary.
► Check that the throttle cable is properly adjus‐
ted – readjust if necessary – see chapter on
"Adjusting the Throttle Cable".
► Check the spark arresting screen (not in all
models, country-specific) in the muffler and
clean or replace if necessary.
18.3 Standard Setting
H
► Turn high speed screw (H) counterclockwise
as far as stop (no more than 3/4 turn).
► Turn the low speed screw (L) clockwise as far
as stop, then turn it back 3/4 turn.
18.4 Adjusting Idle Speed
► Carry out the standard setting.
► Start and warm up the engine.
18.4.1 Engine stops while idling
► Turn the idle speed screw (LA) slowly clock‐
wise until the engine runs smoothly.
18.4.2 Erratic idling behavior, engine stops
even though setting of LA screw has
been corrected, poor acceleration
Idle setting is too lean
► Turn the low speed screw (L) counterclock‐
wise, no further than stop, until the engine
runs and accelerates smoothly.
English
L
L
LA
45