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
approximately 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
Remove the shroud – see "Shroud".
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Pull off the spark plug boot.
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Unscrew the spark plug.
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48
Checking the spark plug
Clean the spark plug if it is dirty
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Check the electrode gap (A) and
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readjust if necessary – see
"Specifications"
Use only resistor type spark plugs of
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the approved range. See the
chapter "Specifications" in this
instruction manual
Correct the problems that have caused
fouling of the spark plug:
too much oil in fuel mix;
–
dirty air filter; or
–
unfavorable running conditions, e.g.
–
operating at part throttle.
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) firmly and securely 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
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with solid, non-threaded terminals
Installing the spark plug
Install the spark plug and connect
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the spark plug boot (press it down
firmly) – reassembly all other parts
in the reverse sequence.
MS 171, MS 181, MS 181 C, MS 211, MS 211 C
1
3
2