Resistance Checks; M A Inte Na Nce And A D J U S T M E N T; L U B R Ic A T Io; R E S Is Tan C E C H E C K - Chevrolet 10 1971 Series Chassis Service Manual

ENGINE-ELECTRICAL 6Y-24
LUBRICATION
The gasoline engine type starting motors have graphite
and oil impregnated bronze bearings and therefore re­
quire no periodic lubrication between major overhauls.

RESISTANCE CHECKS

Although the starting motor cannot be checked against
specifications on the car, a check can be made for exces­
sive resistance in the starting circuit. Place a voltmeter
across points in the cranking circuit as outlined below and
observe the reading with the starting switch closed and
the motor cranking (distributor primary lead grounded to
prevent engine firing).
1. From battery positive post to solenoid battery ter­
minal.
2. From battery negative post to starting motor housing.
3. From solenoid battery terminal to solenoid motor
terminal.
If voltage drop is any of above, check exceeds 0.2 volts,
excessive resistance is indicated in that portion of start­
ing circuit and the cause of the excessive resistance could
be located and corrected in order to obtain maximum
efficiency in the circuit.
Do not operate the starting motor
CAUTION:
continuously for more than 30 seconds to avoid
overheating.
When the solenoid fails to pull in, the trouble may be
due to excessive voltage drop in the solenoid control cir­
cuit. To check for this condition, close the starting switch
CONTACT
FINGER
BRUSH
\
GROUNDED BRUSH HOLDER
M AINTENANCE A N D ADJUSTMENTS
GROMMET
BUSHING
INSULATED BRUSH HOLDER
BRUSH SPRING
Fig. ls-Sta rting M otor Cross Section - Light Duty
and measure the voltage drop between the BATTERY ter­
minal of the solenoid and the SWITCH (S) terminal of the
solenoid.
1. If this voltage drop exceeds 3.5 volts, excessive re­
sistance in the solenoid control circuit is indicated
and should be corrected.
2. If the voltage drop does not exceed 3.5 volts and
the solenoid does not pull in, measure the voltage
available at the SWITCH terminal of the solenoid.
3. If the solenoid does not feel warm, it should pull in
whenever the voltage available at the SWITCH ter­
minal is 7.7 volts or more. When the solenoid feels
warm, it will require a somewhat higher voltage to
pull in.

STARTING M OTOR A N D SOLENOID CHECK

The following checks may be made if the specific gravity
of the battery is 1.215 or higher.
1. If the solenoid does not pull in, measure the voltage
between the switch (S) terminal of the solenoid and
ground with the starting switch closed.
If the solenoid feels warm, allow to
CAUTION:
cool before checking.
If the voltage is less than 7.7 volts, check for ex­
cessive resistance in the solenoid control circuit. If
the voltage exceeds 7.7 volts, remove the starting
motor and check (1) solenoid current draw, (2) start­
ing motor pinion clearance, and (3) freedom of shift
lever linkage.
SOLENOID
PLUNGER
\ FIELD COIL
ARMATURE
TURN SPRING
SHIFT
LEVER
SPIRAL
SPLINES
BUSHING
PINION
STOP
O VERRUNNING
ASSIST CLUTCH
SPRING
10-30 CHEVROLET TRUCK SERVICE MANUAL