Spark Plug - Stihl MS 171 Instruction Manual

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 the spark plug.
N
MS 171, MS 171 C, MS 181, MS 181 C, MS 211, MS 211 C
Checking the Spark Plug
Clean dirty spark plug.
N
Check electrode gap (A) and
N
readjust if necessary – see
"Specifications".
Rectify the problems which have
N
caused fouling 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 injuries or
damage to property.
Use resistor type spark plugs with a
N
properly tightened adapter nut.
Installing the spark plug
Install the spark plug and connect
N
the spark plug boot (press it down
firmly) – reassembly all other parts
in the reverse sequence.
A
1
English
39