Perkins 4.99 - Pre-Engaged Starter Motor; Pre-Engaged Starter Motor Description and Maintenance; Pre-Engaged Starter Motor Testing

ELECTRICAL EQUIPMENT -0.8
STARTER MOTOR-PRE·ENGAGED DRIVE
(See Fig. 0.7)
1. Description-Model M45G or 2M113 with
Model 7S Solenoid.
This starter motor is a four-pole, four-brush earth re-
turn machine with series-parallel connected field coils.
A solenoid-operated pre-engaged drive assembly is
carried on an extension of the armature shaft.
The main feature;"
of this type of drive are as follows:
(a) Positive pinion engagement preventi,ng the pinion
being thrown out of mesh whilst starting.
(b) Dual-purpose plate clutch incorporated in the drive
assembly giving over-speed and over-load protec-
tion.
(c) Self-indexing pinion to ensure smooth engagement
between the pinion and the flywheel teeth before
the starter motor begins to rotate.
(d) Armature braking system to ensure rapid return
to rest when the starter button is released.
2. Routine Maintenance
(a) The starter motor requires no routine maintenance
beyond the occasional inspection of the electrical
connection which must be clean and tight, the
brush gear, and the commutator.
(b) After the starter motor has been in service for
some time, remove the starter motor from the
engine and submit it to a thorough bench inspec-
tion.
1. Brush
wear (this is a fair indication of the amount
of work done). Renew brushes worn to, or ap-
proaching, 5/16 in (7,9 mm) in length.
2. Brush spring tension. Correct tension is 30 - 40
ozf (0,85-1,13 kgf). Renew springs if tension has
dropper below 25 ozf (0,71 kgf).
3. Skim commutator if it is pitted or badly worn.
COPPE.R SOLENO 10
LI~ UNIT
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4. Check bearings for excessive side play of arma-
ture shaft.
5. Check pinion movement.
6. Clean and lubricate the indented bearing inside
the pinion sleeve using a bentonite based grease
for this purpose.
7. Clean and lubricate the indented bronze bearing in
the
intermediate bracket. Use Ragosine 'Molypad'
Molybdenised non-creep oil for this purpose.
3. Servicing
(a) Testing in Position
Switch on the lamps. If the vehicle is not equipped
with lighting, then connect a 0-20 voltmeter across the
battery
terminals before proceeding. Operate the starter
control and watch for the following symptoms:-
The lamps dim or voltmeter rearling drops to about
6 volts. and the motor does not crank the engine.
Check battery (must be at least half-charged) and
battery lugs, (clean and a good earth connection).
Check by hand that engine turns freely.
2. The lamps do not dim, the voltmeter reading re-
mains steady at about 12 volts, and the motor does
not crank the engine.
Connect voltmeter from solenoid terminal 'BAT',
and starter yoke, operate starter:-
No volts indicated
(a) Poor lug connections at battery.
(b) Bad earth connection.
(c) Broken starter lead, battery to starter.
Full volts i.e., 12-14 volts indicated.
(a) Faulty solenoid switch.
(b) Open circuit in starter-check brushes.
ENGAGEMENT
LEvER
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I RETAiN!NG RING
ECCENTR Ie
PIVOT PIN
DRIvE EN'O
BRACKET
BEARING
BUSH
~~~~¥~~~~~=iiiiiiiiiilINTER.MEOIATE BRACKET ~ BEARING BUSH
COMMUTATOR END
BRACKET
Q7
ARMATURE