New Holland WorkMaster 50 Service Manual page 674

Engine starter - Troubleshooting
Problem
Pinion shaft fails to
advance
Pinion motor rotates but
no rotation transmitted to
engine
Motor rotates before
pinion meshes with ring
gear
Pinion meshes with ring
gear but starting motor
fails to turn
Motor fails to stop after
engine starts and key
switch is turned off
Electrical systems - Engine starting system
Possible Cause
Wiring: Open circuit battery, and switch ter-
minal connections.
Wiring: Open circuit, fuse.
Key switch: No contact.
Starter motor: Sleeve bearing burnt out.
Starter motor: Lever broken.
Solenoid: Plunger movement defective or
coil open or shorted.
Starting motor: Clutch defective.
Starting motor: Orbital gear or planetary
gears damaged.
Starter motor: Shift lever damaged.
Starter motor: :Shift lever damaged
Starter motor: Slip ring defective.
Starter motor: Pinion teeth worn.
Starter motor: Pinion push out position de-
fective.
Engine: Ring gear worn.
Solenoid defective
Wiring: Line connecting solenoid to battery
broken or defective ground.
Wiring: Lead wire connecting solenoid to
motor tightened improperly.
Starting motor: Ball bearing locked.
Starting motor: Brush worn.
Starting motor: Improper installation.
Starting motor: Brush spring defective.
Starting motor: Commutator dirty.
Starting motor: Armature of field coil defec-
tive.
Starting motor: Field coil-to-brush connec-
tion defective.
Solenoid: Contact not touching properly.
Solenoid: Contact contacting surface
roughened.
Battery: In discharge state.
Key switch: defective.
Defective solenoid.
47866583_ 02/12/2015
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Correction
Repair or replace.
Replace fuse.
Repair or replace.
Repair or replace.
Replace.
Repair or replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Adjust.
Replace.
Replace.
Repair or replace.
Repair or replace.
Replace.
Replace.
Reinstall.
Replace.
Clean.
Repair or replace.
Replace.
Replace.
Replace.
Recharge or replace.
Replace.
Replace.