Spark Arresting Screen In Muffler; Spark Plug - Stihl MS 231 Instruction Manual

Whenever the low speed adjusting
screw (L) has been adjusted, it is usually
also necessary to readjust the idle
speed adjusting screw (LA).
Correcting the carburetor setting for use
at high altitudes
The setting may have to be marginally
corrected if engine performance is
unsatisfactory at high altitudes:
Make standard setting
N
Let the engine warm up
N
Turn the high speed adjusting
N
screw (H) slightly clockwise (leaner)
– max. up to the stop
NOTICE
After descending from a high altitude,
restore the carburetor setting to the
standard setting.
If you make the setting too lean it will
increase the risk of engine damage
through lack of lubrication and
overheating.
MS 231, MS 231 C, MS 251, MS 251 C
Spark Arresting Screen in
Muffler
If engine performance deteriorates,
N
check the spark arresting screen in
the muffler
Let the muffler cool down
N
1
2
Unscrew the screw (1)
N
Pull out spark arresting screen (2)
N
Clean the dirty spark arresting
N
screen, replace if damaged or
heavily carbonized
Refit the spark arresting screen
N
Fit screw
N

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
Remove the shroud – see "Shroud"
N
Pull off the spark plug boot
N
Unscrew spark plug
N
English
37