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Spark Plug
If the engine is down on power,
N
difficult to start or runs poorly at idle
speed, first check the spark plug.
Fit a new spark plug after about 100
N
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
Turn the cap above the rear handle
N
in the direction of the arrow and
remove the filter cover
1
Unplug spark plug boot (1)
N
Unscrew spark plug
N
34
Checking the Spark Plug
Clean dirty spark plug.
N
Check electrode gap (A) and
N
readjust if necessary – see
"Specifications".
Rectify the problems which have
N
caused fouling of the spark plug.
Possible causes are:
Too much oil in fuel mix.
–
Dirty air filter.
–
Unfavorable running conditions.
–
WARNING
Arcing may occur if the adapter nut (1) is
loose or missing. Working in an easily
combustible or explosive atmosphere
may cause a fire or an explosion. This
can result result in serious injuries or
damage to property.
Use resistor type spark plugs with a
N
properly tightened adapter nut.
Installing the spark plug
A
Screw in the spark plug
N
Press on the spark plug boot (1)
N
firmly
Mount filter cover
N
1
1
MS 651
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