Spark Arresting Screen In Muffler; Checking The Spark Plug - Stihl SR 340 Instruction Manual

Spark Arresting Screen
in Muffler
1
If the engine is down on power or does
not run smoothly at maximum RPM,
check the spark arresting screen (if
fitted) in the muffler.
Wait until engine has cooled down
completely before performing the
following operations.
: Use suitable tool to squeeze ends of
clip (1) together and then lift the clip
away.
: Pull the spark arresting screen (2)
out of the muffler.
: Clean the spark arresting screen.
: If the screen is damaged or heavily
carbonized, fit a new one.
SR 340, SR 420

Checking the Spark Plug

2
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.
English / USA
If engine is down on power, difficult to
start or runs poorly at idling speed, first
check the spark plug.
: Remove spark plug – see "Starting /
Stopping the Engine".
: Clean dirty spark plug.
: Check electrode gap (A) and
readjust if necessary – see
"Specifications".
: Use only resistor type spark plugs
of 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.
Fit a new spark plug after approx.
100 operating hours
or earlier if the electrodes are badly
eroded.
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