17 TUNING THE ENGINE
121
17.5
Carburetor
–
adjusting the idle speed
V00996-10
–
Screw idle air adjusting screw
1
all the way in.
–
Turn the idle air adjusting screw to the specified basic set-
ting.
Info
The basic adjustment is shown under the respective
model.
–
Run the engine until warm.
Guideline
Warm-up time
≥
5 min
Danger
Danger of poisoning
Exhaust gases are toxic and
inhaling them may result in unconsciousness and
death.
–
Always make sure there is sufficient ventilation
when running the engine.
–
Use an effective exhaust extraction system 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. (
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
highest 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.
