Flywheel; Testing For Leaks - Stihl BR 500 Service Manual

7.7

Flywheel

1
– Remove the shroud with rewind
starter, b 5.9
– Unscrew the spark plug and
install the locking screw
4282 890 2700 in its place.
Always use the specified locking
screw. Other locking screws may
damage the piston.
: Unscrew the flywheel nut (1).
2
1
: Screw home the puller
1116 893 0800 (1).
– Tap the puller until the flywheel
(2) is released from its seat.
BR 500, BR 550, BR 600
– Lift away the flywheel.
If the flywheel or magnet poles are
damaged or have turned blue,
install a new flywheel.
– Clean the stub of the crankshaft
and the flywheel hub bore with a
standard commercial, solvent-
based degreasant containing no
chlorinated or halogenated
hydrocarbons, b 13.
Install in the reverse sequence.
: Make sure the flywheel's
key (arrow) engages the slot in
the crankshaft.
– Adjust gap between ignition
module and flywheel, b 8.4
Install all other parts in the reverse
sequence.
7.8

Testing for Leaks

Defective oil seals and gaskets or
cracks in castings are the usual
causes of leaks. Such faults allow
supplementary air to enter the
engine and upset the fuel-air
mixture.
This makes adjustment of the
prescribed idle speed difficult, if not
impossible.
Moreover, the transition from idle
speed to part or full throttle is not
smooth.
The crankcase can be checked
thoroughly for leaks with the
carburetor and crankcase tester
and the vacuum pump.
Always carry out the vacuum test
first and then the pressure test.
After completing the tests, always
install a new muffler gasket.
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