15 TUNING THE ENGINE
15.5
96
Carburetor – adjusting the idle speed
402799-11
–
Screw in idle air adjusting screw
specified basic setting.
Guideline
Idle air adjusting screw
open
–
Run the engine until warm.
Guideline
Warming-up phase
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 effective exhaust extraction when starting or run-
ning the engine in an enclosed space.
–
Adjust the idle speed with adjusting screw
Guideline
Choke function deactivated – The choke lever is pushed in to the
stop. (
p. 16)
Idle speed
–
Turn idle air adjusting screw
the idle speed begins to fall.
–
Note the position and turn the idle air adjusting screw slowly coun-
terclockwise 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 satisfactory
results, the cause may be a wrongly dimensioned idling jet.
If you can turn the idle air adjusting screw to the end with-
out any change of engine speed, mount a smaller idling jet.
After changing the idling jet, start from the beginning with
the adjusting steps.
Following extreme air temperature or altitude changes,
adjust the idle speed again.
1
all the way and turn it to the
2 turns
≥ 5 min
2
.
1,400 ... 1,500 rpm
1
slowly in a clockwise direction until