Engine Running Behavior; Spark Arresting Screen In Muffler - Stihl BR 420 Instruction Manual

English
On all spark plugs:
: Always press the boot (2) firmly on
to the spark plug (3).
20

Engine Running Behavior

If engine running behavior is
unsatisfactory even though the air filter
is clean and the carburetor properly
adjusted, the cause may be in the
muffler.
2
: Have the muffler checked for
contamination (coking).
STIHL recommends that all
maintenance and repair work be carried
out by an authorized STIHL dealer.
3
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.
2
BR 420