Piper SARATOGA PA-32-301 Maintenance Manual page 508

PIPER AIRCRAFT
PA-32-301/301T
MAINTENANCE MANUAL
GENERAL.
DESCRIPTION AND OPERATION.
The D-203 magnetos feature two electrically independent ignition circuits in one housing. A single four
pole rotor provides the magnetic energy for both circuits. This magneto uses an impulse coupling to provide
reliable ignition to engine cranking speed. A single cam operates the main breakers for both magneto circuits.
Suppression of contact point arching and conducted ratio interference is accomplished by feed-thru capacitors
which are mounted in the magneto cover which forms a part of the magneto harness assembly. At low engine
cranking speeds the impulse coupling automatically retards the magneto until the engine is also at its retard
firing position. The spring action of the impulse coupling is then released to spin the rotating magnet and
produce the spark required to fire the engine. After the engine starts, the impulse coupling flyweights do not
engage due to centrifugal action. The coupling then acts asa straight drive and the magneto fires at the normal
firing position of the engine.
-CAUTION -
Ascertain that the primary circuits of both magnetos are grounded
before working on the engine.
TROUBLESHOOTING.
Troubles peculiar to the power plant's electrical system are listed in Chart 7401 along with their probable
cause and suggested remedies. When troubleshooting the engine, ground the magneto primary circuit before
performing any checks on the engine.
74-00-02
Page 74-01
2K1
Revised: February 19, 1982
2K1