Spark Plug - Stihl SR 430 Instruction Manual

English
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.
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Spark Plug

N
If the engine is down on power,
difficult to start or runs poorly at idle
speed, first check the spark plug.
N Fit a new spark plug after about 100
operating hours – or sooner if the
electrodes are badly eroded. Install
only suppressed spark plugs of the
type approved by STIHL – see
"Specifications".
Removing the spark plug
2
N Pull off the spark plug boot (1)
vertically.
N Unscrew the spark plug (2).
Checking the spark plug
N Clean dirty spark plug.
N Check electrode gap (A) and
readjust if necessary – see
"Specifications".
N Rectify the problems which have
caused fouling of the spark plug.
Possible causes are:
– Too much oil in fuel mix.
– Dirty air filter.
– Unfavorable running conditions.
If the spark plug comes with a
detachable adapter nut (1), screw
the adapter onto the thread and
tighten it down firmly to reduce
the risk of arcing and fire.
SR 430, SR 450
A
1