Instruction Manual

Table Of Contents
If the muffler plugs are missing or damaged,
mount new plugs
25 Spark Plug
If the engine is down on power, difficult to start
or runs poorly at idle speed, first check the
spark plug.
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 "Specifica‐
tions".
25.1 Removing the Spark Plug
Remove the shroud – see "Shroud".
Pull off the spark plug boot.
Unscrew the spark plug.
25.2 Checking the Spark Plug
Clean dirty spark plug.
Check electrode gap (A) and readjust if neces‐
sary – see "Specifications".
Rectify the problems which have caused foul‐
ing 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 inju‐
ries or damage to property.
Use resistor type spark plugs with a properly
tightened adapter nut.
25.3 Installing the Spark Plug
Screw home the spark plug, fit the boot and
press it down firmly.
Fit the shroud.
26 Storing the Machine
For periods of 3 months or longer
Drain and clean the fuel tank in a well ventila‐
ted area.
Dispose of fuel properly in accordance with
local environmental requirements.
Run the engine until the carburetor is dry – this
helps prevent the carburetor diaphragms stick‐
ing together.
Remove the saw chain and guide bar, clean
them and spray with corrosion inhibiting oil.
Thoroughly clean the machine – pay special
attention to the cylinder fins and air filter.
If you use a biological chain and bar lubricant,
e.g. STIHL BioPlus, completely fill the chain oil
tank.
English 25 Spark Plug
30 0458-154-8321-C