Instruction Manual

MS 271, MS 271 C, MS 291, MS 291 C
English
37
N If engine performance deteriorates,
check the spark arresting screen in
the muffler
N Let the muffler cool down
N Unscrew the screw (1)
N Pull out spark arresting screen (2)
N Clean the dirty spark arresting
screen, replace if damaged or
heavily carbonized
N Refit the spark arresting screen
N Fit screw
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 Remove the shroud – see "Shroud".
N Move the Master Control lever to the
stop position (0).
N Pull off the spark plug boot.
N Clean away loose dirt from around
the spark plug.
N Insert the combination wrench
through the grommet (1) and turn it
as necessary to engage the spark
plug's hexagon.
N Push the combination fully home
against the cylinder.
N Unscrew the 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
0001BA009 KN
2
1
Spark Plug
5902BA013 KN
5902BA014 KN
1
000BA039 KN
A