FS 38
English
25
Cutting attachment rotates when engine 
is idling
N Turn the idle speed screw (LA) 
counterclockwise until the cutting 
attachment stops moiving and then 
turn the screw another 1/2 to 1 full 
turn in the same direction.
WARNING
If the cutting attachment continues to 
rotate when the engine is idling, have 
your machine checked and repaired by 
your servicing dealer.
Erratic idling behavior, poor acceleration 
(despite correction to setting of LA 
screw).
Idle setting is too lean
N Turn the low speed screw (L) 
counterclockwise, no further than 
stop, until the engine runs and 
accelerates smoothly.
Erratic idling behavior
Idle setting is too rich
N Turn the low speed screw (L) slowly 
clockwise, no further than stop, until 
the engine runs and accelerates 
smoothly.
It is usually necessary to change the 
setting of the idle speed screw (LA) after 
every correction to the low speed 
screw (L).
Fine Tuning for Operation at High 
Altitude
A slight correction of the setting may be 
necessary if engine does not run 
satisfactorily:
N Carry out the standard setting.
N Warm up the engine.
N Turn high speed screw (H) slightly 
clockwise (leaner) – no further than 
stop.
NOTICE
After returning from high altitude, reset 
the carburetor to the standard setting.
If the setting is too lean there is a risk of 
engine damage due to insufficient 
lubrication and overheating.
If engine is down on power, difficult to 
start or runs poorly at idling speed, first 
check the spark plug.
Fit a new spark plug after approx. 100 
operating hours or earlier if the 
electrodes are badly eroded.
Wrong fuel mix (too much engine oil in 
the gasoline), a dirty air filter and 
unfavorable running conditions (mostly 
at part throttle etc.) affect the condition 
of the spark plug. These factors cause 
deposits to form on the insulator nose 
which may result in trouble in operation.
Removing the Spark Plug
N Move the stop switch to 0.
N Pull off the spark plug boot (1).
N Unscrew the spark plug.
Spark Plug