MCi Crusader II 1989 Maintenance Manual page 237

Date 1-1-89
Page 7-17
MC-9 MAINTENANCE MANUAL
any other control switch. and battery, including all ground
connections.
2. Clean and tighten all connections as required.
3. Inspect all switches to determine their condition. From the
vehicle wiring diagram. determine whrch circuits should be
energized with the starting switches closed. Use a voltmeter to
detect any open circuits. ·
4.
If
the battery. w1nng and switches are in satisfactory con-
d1tion. and the engine 1s known to be functioning properly.
remove the motor and follow the test procedures outlined
below
5 With the starting motor removed from the engine. the
armature should be checked for freedom of rotation by prying
the pinion w;th a screwdriver Tight bearings. a bent armature
snatt or a loose pole shoe screw wilt cause the armature to not
turn freely.
6 if the armature does not turn freely. the motor should be
disassembled 1mmed1ately. However.
,t
the armature does
rotate freely, the motor should be given a no-load test before
disassembly
The no-load test may point to specific defects which can be
verified with tests when disassembled. Also. the no-load test
can 1dent1fy open or shorted fields. which are difficult to check
when disassembled The no-load test
?ISO
can be used to
,nd1cate normal operation on a repaired motor before
installation.
NO LOAD TEST
1. Connect a voltmeter from the motor terminal to the
ground return terminal, and use an RPM indicator to measure
armature speed. See figure 7-37.
2. Connect the motor and an ammeter in series with a fully
charged battery of the specified voltage. and a switch in the
open position from the solenoid battery terminal to the
solenoid switch terminal.
3 Close the switch and compare the RPM. current. and
~oltage reading with the specifications in the following table
VOUMETU
SWITCH
CIANICING
MOTOI
Figure 7-37. No-Load Test Setup.
NO LOAD STARTER TEST SPECIFICATIONS
Test Min. Current Max. Current Min. Max.
Starter Voltage
Oraw (Amps) Oraw {Amps) RPM RPM
40MT 1TG-1 -11 20 70
110 5500 9000
42MT liG-: -391 20 €0
;5
6500
i1'00
50MT , 0 G-' -38, 20 95 120 5500
7500
It
1s not necessary to obtain the exact voltage specified in the
chart. as an accurate interpretation can be made by recognizing
that 1f the voltage 1s slightly higher the RPM will be proportion-
ately higher. with the current remaining essentially unchanged.
However. if the exact voltage ,s desired a carbon pile con-
nected across the battery can be used to reduce the voltage to
the specified value
If more than one 12-volt battery is used. connect the carbon
pile to only one of the 12-volt batteries. Make disconnections
oniy with the switch open Interpret the test results as follows:
NOTE: Rated current draw and no-load
speed indicates normal condition of the
starting motor.
4 Low free speed and high current draw indicate.
a. Too much friction - tight. dirty. worn bearings. bent
.,rmature shaft or loose pole shoes allowing armature to drag.
b. Shorted armature. This can be further checked on a
growler after disassembly.
c. Grounded armature or fields. Check further after dis-
assembly.
5. Failure to operate with high current draw indicates:
a. A direct ground in the terminal or fields.
b. "Frozen" bearings (this should have been determined
by turning the armature by hand).
6. Failure to operate with no current draw indicates:
a Open field circuit This can be checked after disassem-
bly by inspecting terminal connections and tracing circuit with
a test 1amp
b Open armature coils Inspect the commutator for badly
burned bars after disassembly
c Broken brush springs. worn brushes high 1nsulat1on
between the commutator bars or other causes which would
prevent good contact between the brushes and commutator
7. Low no-load speed and low current draw indicate high
internal resistance due to poor connections. defective leads.
dirty commutator and causes listed in Number 6.
8 High free speed and high current draw indicate shorted
field If shorted fields are suspected. replace the field coil
assembly and check for improved performance
LUBRICATION
1 All bearings. wicks and oil reservoirs should be saturated
with SAE No 20 011
2 Place a 11ght coat of lubncant Delco Remy No. 1960954 on
the wasner located on the shaft between the armature and shift
lever housing.
NOTE: Sintered bronze bearings used in
these motors ha_ve a dull finish, as com-
pared 'to the early type machined. cast
bronze bearings which had a shiny finish.