FS 510 C-M, FS 560 C-M
English
36
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.
Installing the Spark Plug
N Screw the spark plug into the 
cylinder.
N Press the spark plug boot firmly 
onto the spark plug.
N Fit the cap (1) on the shroud from 
the rear and push the lug (2) into the 
opening (3) in the shroud at the 
same time.
N Swing the cap forwards onto the 
shroud, insert and tighten down the 
screw (4) firmly.
If engine running behavior is still 
unsatisfactory after servicing the air filter 
and adjusting the throttle cable, the 
cause may be the muffler.
Have the muffler checked by a servicing 
dealer for contamination 
(carbonization).
STIHL recommends that you have 
servicing and repair work carried out 
exclusively by an authorized STIHL 
servicing dealer.