MS 290, MS 310, MS 390
English
36
In some countries, the muffler is fitted
with a spark arresting screen.
N
If engine performance deteriorates,
check the spark arresting screen in
the muffler
N
Let the muffler cool down
N
Unscrew and remove the nuts (1)
N
Remove the cover (2)
N
Remove the spark arresting
screen (3)
N
Clean the dirty spark arresting
screen, replace if damaged or
heavily carbonized
N
Refit the spark arresting screen
N
Reinstall cover
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
N
Move the Master Control lever to 0
N
Turn the knob above the rear handle
to the left – slot vertical
N
Pull off the carburetor box cover
toward the rear
N
Lift off the prefilter (1)
N
Unplug spark plug boot (2)
N
Unscrew spark plug
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.
Spark Arresting Screen in
Muffler
1
1
1
139BA020 KN
139 BA021 KN
3
2
Spark Plug
139BA016 KN
1
139BA001 KN
139BA002 KN
2
000BA039 KN
A
