Gear Drive 12V
CHECKING THE STARTER MOTOR
A performance test of the starter motor may be made in
the following manner.
Equipment Needed -
A tachometer capable of reading 10,000 RPM.
A 12 volt battery 0.3 volts.
An ammeter capable of reading 100 amperes.
Connect the starter motor, battery and ammeter as
shown on the accompanying illustration. See Fig. 125.
Fig. 125 - Checking Stator Motor Performance
Insert the tachometer in the end of the starter motor and
activate the starter motor. A starter motor in good
condition will be within the following specifications.
Starter motor RPM 5500 minimum.
Current draw (amperes) 60 maximum (Disregard
If the starter motor does not perform satisfactorily, the
following should be checked and corrected if necessary.
A binding or seizing condition in the starter motor
Starter motor brushes sticking in brush holders.
A dirty or worn armature commutator or brushes.
A shorted, open or grounded armature or field
DISASSEMBLY OF STARTER MOTOR
(See checking starter motor drive if repair, cleaning or
replacement of drive assembly is necessary.)
Remove thru bolts and commutator end cap. The
armature, drive cap and gear drive may be removed as
an assembly. See Fig. 126.
Fig. 126 - Removing Thru Bolts
Clean all dirt accumulations from the armature, end
caps, etc. The bearings, housing and armature should
not be soaked in a cleaning solution. The armature
commutator may be cleaned with a 000 sand paper. Do
not use emery cloth, as emery will embed in the
commutator and cause rapid wear. If it is suspected that
the armature or field coil is defective, a new armature or
field coil should be tried in the motor. If proper testing
equipment is available, check the suspected armature or
field coil to determine if it is defective. The brushes
should be checked for poor seating, weak brush springs
or dirt and oil. Check to be sure brushes are not sticking
in their respective brush holders. See Fig. 127.
Fig. 127 - Checking Brushes