TUNING THE ENGINE 15
103
15.5 Carburetor - adjusting the idle speed
402799-11
–
Screw in idle air adjusting screw
1
all the way and turn it to
the specified basic setting.
Info
The basic adjustment is shown under the respective
model.
– Run the engine until warm.
Guideline
Warming-up phase ≥ 5 min
Danger
Danger of poisoning Exhaust gases are toxic and inhal-
ing them may result in unconsciousness and death.
– Always make sure there is sufficient ventilation
when running the engine.
– Use effective exhaust extraction when starting or
running the engine in an enclosed space.
–
Adjust the idle speed with adjusting screw
2
.
Guideline
Choke function deactivated – The choke lever is pushed in
to the stop. ( p. 16)
Idle speed 1,400 … 1,500 rpm
–
Turn idle air adjusting screw
1
slowly in a clockwise direc-
tion until the idle speed begins to fall.
– Note the position and turn the idle air adjusting screw slowly
counterclockwise until the idle speed again begins to fall.
– Adjust to the point between these two positions with the high-
est idle speed.
Info
If there is a big engine speed rise, reduce the idle
speed to a normal level and repeat the above steps.
If the procedure described here does not lead to sat-
isfactory results, the cause may be a wrongly dimen-
sioned idling jet.
If you can turn the idle air adjusting screw to the end
without any change of engine speed, mount a smaller
idling jet.
After changing the jet, start from the beginning with
the adjusting steps.
Following extreme air temperature or altitude changes,
adjust the idle speed again.