11-50. STARTING MOTOR CONTROL CIRCUIT.
a. Inspect the control circuit wiring between the battery, solenoid and manual starting switch for breaks, poor
connections and faulty insulation. Tighten all ground connections and make sure solenoid is firmly mounted and
makes a good ground connection.
b. Check the voltage loss across the switch contacts during normal starting. If loss is in excess of 0.2 volts
per 100 amps, the solenoid should be replaced.
c. If solenoid fails to operate when the manual starting switch is turned on, or if it fails to release when the
manual starting switch is released, it should be replaced.
11-51. STARTING MOTOR SERVICE TEST SPECIFICATIONS. Prestolite specifications for 12 volt starting
motors installed as standard equipment on PA-28-161 CADET airplanes are as follows:
TABLE XI-V. STARTING MOTOR SPECIFICATIONS (PRESTOLITE)
Motor Model
MZ-4204/MZ-4206/MZ/MZ-4218
Min. Brush Tension
32 oz.
Max. Brush Tension
40 oz
No Load Test (77° F)
Volt
10
Max. Amps
75
Min R.P.M.
2000
Stall Torque
Amps
560
Min. Torque, Ft. lbs
38.0
Approx. Volts
4.0
Pinion Position*
Drive at rest
1.748in. - 1.855 in.
Drive extended
2.388 in. - 2.495 in.
* This dimension is measured from the centerline of the mounting hole nearest hole the
drive end head to the edge of the pinion
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
ELECTRICAL SYSTEM
2D20
