Spark Plug - Stihl MS 250 Instruction Manual

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
Depress throttle trigger lockout and
N
throttle trigger at the same time and
move the Master Control lever to
choke closed l.
Turn the knob 90° to the left.
N
Lift off the carburetor box cover
N
vertically.
MS 250
4
3
Place fingers behind the air filter (3),
N
press thumbs against the housing,
swing the filter in the direction of the
rear handle and remove it.
Remove the shutter (4).
N
Pull off the spark plug boot.
N
Unscrew the spark plug.
N
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.
English
A
1
37