Cranking; Maintenance Of Starting System; Starting Motor; Overhaul Of Starting Motor - Piper PA-31-350 Maintenance Manual

PIPER AIRCRAFT
T-1020
MAINTENANCE MANUAL
CRANKING.
MAINTENANCE OF STARTING SYSTEM.
The starting circuit should be inspected at regular intervals, the frequency of which should be determined
by the amount of service and the conditions under which the aircraft is operated. It is recommended that such
inspection be made at least twice a year and include the following:
1. 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 condition. 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 batttery cells.
2. 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:
A. Voltage loss from insulated battery post to starting motor terminal - 0.3 volt maximum.
B. Voltage loss from battery ground post to starter frame - 0.1 volt maximum.
-NOTE-
If voltage loss is greater than the limits outlined in steps A and B,
additional tests should be made over each part of the circuit to
locate the high-resistance connections.
3. No lubrication is required on the starting motor except at the time of overhaul. Then lubricate the
entire shaft under Bendix Drive, fill grooves in armature 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.
4. The starting motor should be operated for a few seconds with the ignition switch off to make sure that
the pinion engages properly and that it turns freely without binding or excessive noise. Then the
engine should be started two or three times to see that the pinion disengages properly when the engine
is turned off.
STARTING MOTOR.
OVERHAUL OF STARTING MOTOR.
If during the above inspection any indication of starting motor difficulty is noted, the starting motor should
be removed from the engine for cleaning and repair.
REMOVAL OF STARTING MOTOR.
To remove the starting motor from the engine, first disconnect the ground cable from the battery post to
prevent short circuiting. Disconnect the lead from the starting motor terminal, then take out the mounting bolts.
The motor can then be lifted off and taken to the bench for overhaul.
80-10-04
4I14
Page
80-02
Issued: September 2, 1981