Spark Plug - Stihl BT 131 Instruction Manual

English

Spark Plug

If there is a loss of engine power, the
machine is difficult to start or runs poorly
at idle, first check the spark plug.
Install a new spark plug after approx.
100 operating hours or earlier if the
electrodes are eroded/corroded.
The wrong fuel mix (too much engine oil
in the gasoline), a dirty air filter and
unfavorable running conditions (mostly
at part throttle etc.) affect the condition
of the spark plug. These factors cause
deposits to form on the insulator nose,
which may degrade performance.
Removing the Spark Plug
1
2
3
Remove the cover (1).
N
Pull off the spark plug boot (2).
N
Unscrew the spark plug (3).
N
22
Checking the Spark Plug
Clean dirty spark plug.
N
Check electrode gap (A) and
N
readjust if necessary – see chapter
"Specifications."
Use only resistor type spark plugs of
N
the approved range.
Rectify problems which have caused
fouling of spark plug:
too much oil in fuel mix,
–
dirty air filter,
–
unfavorable running conditions, e.g.
–
operating at part load.
A
WARNING
To reduce the risk of fire and burn injury,
use only spark plugs authorized by
STIHL. Always press the spark plug
boot (1) snugly onto the spark plug
terminal (2).
Do not use a spark plug with a
detachable SAE adapter terminal (3).
Arcing may occur that could ignite
combustible fumes and cause a fire.
This can result in serious injuries or
damage to property.
Only use resistor type spark plugs
N
with solid, non-threaded terminals
Installing the Spark Plug
Screw the spark plug (3) into the
N
cylinder.
Tighten down the spark plug (3) with
N
the combination wrench.
1
3
2
BT 131