MS 441
English
39
Erratic idling behavior, poor 
acceleration (even though low speed 
screw is open 1/4 turn)
N Idle setting is too lean: Turn the low 
speed screw (L) counterclockwise 
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 Check the standard setting.
N Warm up the engine.
N Turn high speed screw (H) slightly 
clockwise (leaner) – no further than 
stop.
In some countries the muffler is 
equipped with a spark arresting screen.
N If the engine is down on power, 
check the spark arresting screen in 
the muffler.
N Wait for the muffler to cool down.
N Take out the screw (1).
N Pull out the spark arresting 
screen (2).
N Clean the spark arresting screen. If 
the screen is damaged or heavily 
carbonized, fit a new one.
N Refit the spark arresting screen.
N Insert the screw and tighten it down 
firmly.
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 Master Control lever to the 
stop position (0).
N Use the combination wrench to 
open the fasteners (1) in the 
direction of the arrow.
N Remove the carburetor box 
cover (2).
Spark Arresting Screen in 
Muffler
Spark Plug