Catalytic Converter; Spark Plug - Stihl BG 55 Instruction Manual

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Catalytic Converter

Power tools with a catalytic converter
(depending on model) must be run on a
50 : 1 mixture of unleaded gasoline and
STIHL two-stroke engine oil or
equivalent two-stroke engine oil – see
chapter on "Fuel".
The catayltic converter integrated in the
muffler reduces the harmful emissions in
the exhaust gas.
The correct carburetor setting (if
adjustable) and strict observance of the
prescribed mix ratio of gasoline and two-
stroke engine oil are essential to
minimize harmful emissions and ensure
a long catalytic converter service life.
20

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
1
Pull off the spark plug boot (1).
N
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.
BG 55, BG 65, BG 85, SH 55, SH 85
A