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ELECTRICAL SYSTEMS
CRANKING SYSTEM
10-49
solenoid relay to which .the wire with black
parallel tracer is connected. CAUTION: Do not
operate cranking motor more than 30 seconds
at a time without pausing to allow motor to
cool for at least two mimutes; otherwise, over-
heating and damage to motor may result. After
cleaning commutator, blowout all dust from
cranking
motor.
5. Check motor and solenoid switch attach-
ing bolts to make sure these units are solidly
mounted. Inspect and manually check all wiring
connections at solenoid switch, solenoid relay,
generator regulator, generator, accelerator vac-
uum switch, ignition switch, No.1 terminal of
headlamp lighting switch, charge indicator, and
neutral safety switch (Dynaflow Drive cars
only). Make sure that all these connections in
the cranking motor and control circuits are
clean and tight.
It
is advisable to
te~t
the crank-
ing circuit to make certain that excessive re-
sistance does not exist. See paragraph
10-37.
Figure 10-55-Cranking Voltage Test Connections
10-37 VOLTAGE TEST OF CRANKING
MOTOR AND SOLENOID SWITCH
The voltage across the cranking motor and
switch while cranking the engine gives a good
indication of any excessive resistance. NOTE:
Engine must be at normal operating tempera-
ture when test is
made.
1. Inspect battery and cables (par. 10-17)
to make certain that battery has ample capa-
city for cranking and ignition.
2. Connect jumper wire to primary ter-
minal of distributor and to ground on engine,
so that engine can be cranked without
firing.
3. Connect voltmeter positive
(+)
lead to
the motor terminal on solenoid switch; connect
voltmeter negative (-) lead to ground on en-
gine. See figure 10-55.
4. Turn ignition switch on, crank engine
and take voltmeter reading as quickly as pos-
sible.
If
cranking motor turns engine at normal
cranking speed with voltmeter reading 4.5 or
more volts, the motor and switch are satisfac-
tory.
If
cranking speed is below normal and
voltmeter reading is 4.5 or greater, the
crank-
ing motor is defective.
5.
If
cranking motor turns engine at low
rate of speed with voltmeter reading less than
4.5 volts, test solenoid switch contacts as fol-
lows.
Figure 10-56-Solenoid Switch Contact Test Connections
6. Connect voltmeter negative (-) lead to
the motor terminal of solenoid switch, and con-
nect positive
(+)
lead to battery terminal of
switch. Turn voltmeter switch to low voltage
scale. See figure 10-56.
7. Turn ignition switch on, crank engine,
and take voltmeter reading as quickly as pos-
sible. Voltmeter will read not more than
YI0
volt if switch contacts are satisfactory.
If
volt-
meter reads more than
%0
volt, switch should
be repaired or replaced.
10-38 TEST AND ADJUSTMENT OF
SOLENOID SWITCH RELAY
When the solenoid switch relay is operating
properly, the contact points will close at 1.2 to
1.8 volts, and will open at not less than .6 volts,
when tested with relay cold (at room tempera-
ture). The relay must cut in at this low volt-
age so that it will operate during cold weather
with a low battery.
The solenoid switch relay should not be tam-
pered with unless the proper test equipment is
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