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ELECTRICAL SYSTEMS
CRANKING SYSTEM
10-51
BEND ARMATURE
STOP
TO ADJUST POINT OPENING
POINT OPENING
.0 25" GAUGE
Figure lO-59-Relay Contact Point Adjustment
voltage, or bend up to decrease voltage. See
figure 10-60. Recheck closing voltage after each
adjustment.
6. Check sealing voltage by continuing to
raise voltage slowly after points close until
armature seals to core. (This is usually accom-
panied by an audible click.). Sealing voltage
should be not more than 3 volts.
ARMATURE SPR
I NG
POST
!BEND DOWN TO INCREASE
OR UP TO DECREASE
CL
OS I NG
VOLTAGE)
Figure lO-60-Relay Closing Voltage Adjustment
7. Cut out all resistance to completely sat-
urate coil, then slowly reduce voltage until con-
tact points open, and note voltage. Opening
voltage should be not less than .6 volt.
8. Sealing and opening voltages can be ad-
justed by varying the adjustment of air gap or
closing voltage within specification limits. Clos-
ing voltage should be rechecked after adjust-
ments of sealing or opening voltage.
9. Install switch cover and gasket and in-
stall cranking motor on engine.
10-39 SOLENOID SWITCH TEST AND
REPAIRS - CRANKING MOTOR
ON BENCH
a. Testing Solenoid Switch Windings
When the cranking motor is removed from
engine, the solenoid switch windings can be
tested with switch either on or off the cranking
motor, if the required test instruments
are
available. Two tests must be made to determine:
(1) Current draw of both windings in parallel;
(2) Current draw of hold-in winding alone.
1. Remove switch-to-motor connector, and
remove switch cover and gasket.
2. Connect 6-volt battery, a variable re-
sistance, and an ammeter of 75 amperes capa-
city in series with base of solenoid and the
terminal on relay to which solenoid windings
are soldered. Connect voltmeter between sole-
noid base and the solenoid winding leads at re-
lay terminal. Ground the switch motor terminal
to solenoid base with a jumper wire.
3. Slowly adjust resistance until voltmeter
reads 5 volts and note current draw on
ammeter.
Current draw of both windings in parallel should
be 65 to 71 amperes at 5 volts. CAUTION: Do
not close the solenoid relay contact points when
making this test since this would cause a direct
short when the solenoid switch operated.
4. Remove jumper wire and readjust re-
sistance until voltmeter reads 5 volts. The cur-
rent draw of the hold-in winding alone should
be 12 to 14 amperes at 5 volts.
5.
If
the solenoid windings do not test
within the specifications given, the solenoid
switch assembly requires replacement.
b. Replacement of Parts
The solenoid switch may be disassembled by
removal of parts as shown from right to left in
figure 10-61.
For replacement of the relay assembly it is
necessary to unsolder the solenoid winding
leads. When resoldering leads use only rosin
flux-never use acid flux when soldering elec-
trical connections.
It is not necessary to unsolder the solenoid
winding leads in order to replace the switch
contact disk or terminal studs.
When assembling switch, note that two fiber
washers, a plain washer, and a lock washer go
on each terminal stud before installing the first
nut.
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