4.4.7 Contact Set - Stihl 009 User Manual

STIHL 009, 010, 011
Discharging the condenser
should briefly move to about 0.2 (µF)
in measuring range "µFx1" (/-µF =
microfarad). If this is not the case the
condenser is faulty and a new one
must be installed. Always discharge
the condenser after each test by
shorting it out (connecting lead to
ground).
If the Bosch tester EFAW 106 A is
used for the test, follow the
instructions supplied with the unit.
If the condenser is faulty, the
complete contact set must be
replaced (4.4.5.3).
Finish off by refitting the contact set,
flywheel and fan housing.

4.4.7 Contact Set

The contact breaker set consists of a
fixed contact, which is connected to
ground, and a moving contact breaker
lever which is insulated from ground
and connected to the ignition coil's
primary connection and the
condenser. The contact set functions
as a switch which closes the primary
circuit and opens it again at the point
of ignition.
The service life of the heel on the
contact breaker lever is greatly
dependent on proper lubrication. It is
therefore important to insure that the
grease impregnated lubricating felt in
the contact plate is always in good
condition.
The contact breaker points gradually
wear as a result of erosion. Eroded
contacts widen the breaker point gap
and cause ignition timing to be
advanced and the magneto edge gap
to be reduced.
Partly eroded contact breaker points
can be reset but badly burnt points
necessitate immediate replacement of
the complete contact set. To do this,
remove fan housing and flywheel,
unscrew the two contact set mounting
screws and one screw on the cable
clamp and then take out the contact
set. Push cable clamp out of the way,
take out fastening screw and remove
contact spring and primary lead.
When installing the new contact set
make sure the cable clamp presses
Top:
Removing contact set and cable clamp
Bottom:
Removing mounting screw
the primary lead firmly into the
housing slot. The primary lead must
not touch the flywheel. Furthermore,
the cylindrical pin on the underside of
the contact plate must be properly
seated in the locating hole provided in
the crankcase.
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