L
H
LA
N
Turn high speed screw (H)
counterclockwise as far as stop (no
more than 3/4 turn).
N
Turn the low speed screw (L)
carefully clockwise as far as stop,
then turn it back 1 turn.
N
Start and warm up the engine.
Adjusting Idle Speed
Engine stops while idling
N
Check the standard setting.
N
Turn the idle speed screw (LA)
slowly clockwise until the engine
runs smoothly.
Erratic idling behavior, engine stops
even though setting of LA screw has
been corrected, poor acceleration
Idle setting is too lean
N
Turn the low speed screw (L) slowly
counterclockwise until the engine
runs and accelerates smoothly.
Erratic idling behavior
Idle setting is too rich
N
Turn the low speed screw (L)
clockwise until the engine runs and
accelerates smoothly.
SR 430, SR 450
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 in
Mountains or at Sea Level
A slight correction of the setting may be
necessary if engine power is not
satisfactory when operating at high
altitude or at sea level.
N
Check the standard setting.
N
Warm up the engine.
At high altitude
N
Turn high speed screw (H)
clockwise (leaner) – no further than
stop.
If the setting is too lean there is a
risk of engine damage due to
insufficient lubrication and
overheating.
At sea level
N
Turn high speed screw (H) slightly
counterclockwise (richer) – no
further than stop.
Spark Plug
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
2
N
Pull off the spark plug boot (1)
vertically.
N
Unscrew the spark plug (2).
English
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