Spark Plug - Stihl MS 261 C-MQ Instruction Manual

Spark Plug

If engine is down on power, difficult to
start or runs poorly at idling speed, first
check the spark plug.
Fit a new spark plug after approx. 100
operating hours or earlier if the
electrodes are badly eroded.
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 result in trouble in operation.
Removing the Spark Plug
Remove the shroud – see "Shroud".
N
Pull off the spark plug boot.
N
Clean away loose dirt from around
N
the spark plug.
MS 261 C-MQ
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Insert the combination wrench
N
through the grommet (1) and turn it
as necessary to engage the spark
plug's hexagon.
Push the combination fully home
N
against the cylinder.
Unscrew the spark plug.
N
Checking the Spark Plug
Clean dirty spark plug.
N
Check electrode gap (A) and
N
readjust if necessary – see
"Specifications."
Use only resistor type spark plugs of
N
the approved range.
Rectify problems that 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 spark plug boot (1)
snugly onto spark plug terminal (2) of the
proper size. (Note: If terminal has
detachable SAE adapter nut, it must be
securely attached.) A loose connection
between spark plug boot and ignition
wire connector in the boot may create
arcing that could ignite combustible
fumes and cause a fire.
English
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