English
Spark Plug
If the engine is down on power,
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difficult to start or runs poorly at idle
speed, first check the spark plug.
Fit a new spark plug after about 100
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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
Pull off the spark plug boot (1).
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Unscrew the spark plug (2).
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20
Checking the spark plug
Clean dirty spark plug.
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Check electrode gap (A) and
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readjust if necessary – see
"Specifications".
Rectify the problems which have
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caused fouling of the spark plug.
Possible causes are:
Too much oil in fuel mix.
–
Dirty air filter.
–
Unfavorable running conditions.
–
WARNING
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.
Installing the spark plug
A
Screw the spark plug (3) into the
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cylinder and fit the boot (2) (press it
down firmly).
1
2
3
BR 500, BR 550, BR 600