TRUCK SERVICE MANUAL
Fig. 3 Sectional View of Staring Motor with Heavy Duty Sprag Clutch
pinion is engaged with the flywheel, the pinion will
The starting motors which utilize the large oil reservoirs
not be permitted to disengage until the engine has
and the "0" ring are called "long life motors".
started and the solenoid circuit is interrupted.
Some of the heavy duty starting motors feature a
On chassis operating under normal conditions no
seal between the shaft and lever housing, and all of the
maintenance to these starting motors will be required.
heavy duty starting motors with the enclosed shift lever
When the engine is overhauled the starting motor should
have a rubber boot or linkage seal over the solenoid
be disassembled, inspected, cleaned, tested and any
plunger. These seals prevent the entry of dirt and oil into
the motor main frame.
TROUBLE SHOOTING THE STARTING CIRCUIT
When trouble develops in the starting motor
Lubrication is provided for the bronze bushings
system, and the starter motor cranks the engine slowly
located in the commentator end frame, lever housing
or not at all, several preliminary checks can be made to
and the nose housing, by an oil saturated wick that
determine whether the trouble is in the battery, starting
projects through each bushing and contacts the
motor, wiring circuit between them, or elsewhere. Many
armature shaft. Oil can be added to the wicks by
conditions besides defects in the motor can result in poor
removing the pipe plugs.
The starting motor should be lubricated whenever
To obtain full performance from a starting motor or
it is disassembled with SAE10 oil.
to determine the cause of abnormal operation, the motor
All the wicks should be saturated, reservoirs filled and
should be subjected to one or more of the following tests.
the splines underneath the clutch should be lubricated
These tests are performed with the starter motor
with a light coat of oil.
removed from the engine. Failure of the motor to
perform according to the specifications will require
Some of the starting motors are equipped with a
disassembly and further checks or adjustments made.
large oil reservoir for each wick, also "0" rings are used
at various locations to resist entry of dirt and moisture.
NOTE: All starting motor tests should be made with
engine and battery at room temperature (not cold).