Piper COMANCHE PA-24-180 Service Manual page 585

PIPER COMANCHE SERVICE MANUAL
ground. The manetic force created in the rmature combined with that created in the field wind-
ings begins to turn the armature.
The gear cuton the drive endof the armature shaftextends through the gear housing, where
it is supported by a roller bearing. The gear mates with the teeth of the reduction gear that drives
the Bendix shaft. The shaft is keyed to the reductin gear. The Bendix drive is held in position
en the shaft by a "spiral"
pin. The shaft is supported in the gear housing by a closed end roller
bearing and in the pinion housing by a graphitized bronze bearing.
When the armature turns the reduction gear, the Bendix drive pinion meshes with the fly-
wheel ring gear by inertia and action of the screw threads within the Bendix sleeve. A detent pin
engages in a notch in the screw threads which prevents demeshing if the engine fails to start
when the starting circuit is de-energized.
When the engine reaches a predetermined speed, centrifugal action forces the detent pin
out of the notch in the screw shaft and allows the pinion tb demesh from the flywheel.
9-77. Maintennce. The starting circuit should be inspected at regu.. intervals, the frequency
of which should be determined by the amount of service and conditions under which the vehicle
is operated. It is recommended that such inspection be made at least twice a year and include
the following:
a. The battery should be checked with a hydrometer to be sure it is fully charged and filled
to the proper level with approved water. A load test should be made to determine battery can-
dition. If dirt and corrosion have accumulated on the battery, it should be cleaned with a solution
of baking soda and water. Be sure none of the solution enters the battery cells.
b. The starting circuit wiring should be inspected to be sure that all connections are clean
and tight and that the insulation is sound. A voltage loss test should be made to locate any high-
resistance connections that would affect starting motor efficiency. This test is made with a low-
reading voltmeter while cranking the engine or at approximately 100 amperes, and the following
limits should be used:
1. Voltage loss from insulated battery post to starting motor terminal - 0.3-volt maimunm.
2. Voltage loss from battery round post to starter frame - O.1-volt maximum.
NOTE
If voltage loss is greater than the above limits, additional tests
should be made over each part of the circuit to locate the high-
resistance connections.
c. No lubrication is required on the starting motor except at the time of overhaul. Then lubri-
cate the entire shaft under Bendix Drive, fill grooves in annature shaft at drive end and pack
gear box with 1.3 to 2.0 ounces of Lithium Soap Base Grease ;1925 Molytex "O" or equivalent.
d. The starting motor should be operated for a few seconds with the ignition switch off to
make sure that the pinuon engages properly and that it turns freely without binding or excessive
noise. Then the engine should be started two or three times to see thar the pinion disengages
properly when the engine is turned off.
ELECTRICAL SYSTEM
ISSUED: 8/18/72
3 C15