Spark Arresting Screen In Muffler; Spark Plug - Stihl MS 290 Instruction Manual

English
Spark Arresting Screen in
Muffler
In some countries, the muffler is fitted
with a spark arresting screen.
If engine performance deteriorates,
N
check the spark arresting screen in
the muffler
Let the muffler cool down
N
1
1
1
Unscrew and remove the nuts (1)
N
3
Remove the cover (2)
N
Remove the spark arresting
N
screen (3)
Clean the dirty spark arresting
N
screen, replace if damaged or
heavily carbonized
Refit the spark arresting screen
N
Reinstall cover
N
36

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
Move the Master Control lever to 0
N
2
Turn the knob above the rear handle
N
to the left – slot vertical
Pull off the carburetor box cover
N
toward the rear
Lift off the prefilter (1)
N
N
N
Checking the Spark Plug
N
N
N
Possible causes are:
–
1
–
–
2
Unplug spark plug boot (2)
Unscrew spark plug
A
Clean dirty spark plug.
Check electrode gap (A) and
readjust if necessary – see
"Specifications".
Rectify the problems which have
caused fouling of the spark plug.
Too much oil in fuel mix.
Dirty air filter.
Unfavorable running conditions.
MS 290, MS 310, MS 390