Instruction Manual

MM 55, MM 55 C
English
20
Engine stops while idling
N Turn the idle speed screw (LA)
clockwise until the engine runs
smoothly – the cutting/working
attachment must not rotate.
Cutting/working attachment runs when
engine is idling
N Turn the idle speed screw (LA)
counterclockwise until the
cutting/working attachment stops
moving and then turn the screw
another 1/2 to 1 full turn in the same
direction.
WARNING
If the cutting/working attachment
continues to run 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 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.
Remove the spark plug
N Move the slide control to STOP-0
N Unplug spark plug boot (1)
N Unscrew spark plug
469BA059 KN
L
Spark Plug
1
232BA081 KN