Page 88 of 788

STARTING SYSTEM
ENGINE ELECTRICAL16-24
MAGNETIC SWITCH HOLD-IN TEST
1. Disconnect the field coil wire from the M-terminal
of the magnetic switch.
CAUTION
This test must be performed quickly (in less than
10 seconds) to prevent the coil from burning.
2. Connect a 12-volt battery between the S-terminal
and body.
3. Manually pull out the pinion as far as the pinion
stopper position.
4. If the pinion remains out, everything is in order. If
the pinion moves in, the hold-in circuit is open.
Replace the magnetic switch.
FREE RUNNING TEST
1. Place the starter motor in a vise equipped with
soft jaws and connect a fully-charged 12-volt
battery to the starter motor as follows:
2. Connect a test ammeter (100-ampere scale) and
carbon pile rheostat in series between the battery
(+) terminal and starter motor terminal.
3. Connect a voltmeter (15-volt scale) across the
starter motor.
4. Rotate the rheostat to full-resistance position.
5. Connect the battery cable from the battery (-)
terminal to the starter motor body.
6. Adjust the rheostat until the battery voltage shown
on the voltmeter is 11 V.
7. Confirm that the maximum amperage is within the
specifications and that the starter motor turns
smoothly and freely.
Current:
<4G1> maximum 95 Amps
<4G6> maximum 90 Amps
AK300650AB
<4G1>
S
BMWire
Battery Starter
motor
AKX01244
<4G6>
S
B M
Battery
Starter
motorWire
AF
AK300651AB
<4G1>
S
A M
V BCarbon-pile rheostat
Battery
VoltmeterAmmeter
Starter
motor
AKX01246
<4G6>
S
M
BAmmeter
Carbon-pile
rheostat
Battery
Starter
motor
Voltmeter
AF
A
V
Page 89 of 788
STARTING SYSTEM
ENGINE ELECTRICAL16-25
MAGNETIC SWITCH RETURN TEST1. Disconnect the field coil wire from the M-terminal
of the magnetic switch.
CAUTION
This test must be performed quickly (in less than
10 seconds) to prevent the coil from burning.
2. Connect a 12-volt battery between the M-terminal
and body.
WARNING
Be careful not to get your fingers caught
when pulling out the pinion.
3. Pull the pinion out and release. If the pinion
quickly returns to its original position, everything is
operating properly. If it doesn't, replace the
magnetic switch.
AK300652AB
<4G1>
S
BMWire
Battery Starter
motor
AKX01248
<4G6>
S
B M
Battery
Starter
motorWire
AF
Page 90 of 788
Page 91 of 788
Page 92 of 788

STARTING SYSTEM
ENGINE ELECTRICAL16-28
2. Measure the diameter of the commutator.
Standard value: 29.4 mm
Limit: 28.8 mm
3. Measure the depth of the undercut between
segments.
Standard value: 0.5 mm
Limit: 0.2 mm
BRUSH HOLDER
Push the brush into the brush holder to make sure
that the spring is working on the brush.
If the spring is not working, replace the brush holder.
OVERRUNNING CLUTCH
1. Make sure that the pinion cannot be turned
counterclockwise and can be turned clockwise
freely.
2. Check the pinion for abnormal ware and damage.
BRUSHES
1. Check the commutator contacting surface of each
brush for abnormal roughness. Also check the
height of the brush. Replace the brush holder if
the height is lower than the limit.
Limit: 7.0 mm
2. When the contact surface of the brush is rectified
or the brush holder is replaced, recondition the
contact surface with sandpaper wrapped around
the commutator.
ARMATURE COIL
1. Check the armature coil for short circuit as
follows:
AK202715
AK202711
SegmentUndercut
Mica
AB
AK201187
AK202710
Free
Lock
AB
AK202846
Brush
height
AB
Page 93 of 788

STARTING SYSTEM
ENGINE ELECTRICAL16-29
2. Set the armature in a growler.
CAUTION
Clean the surface of the armature thoroughly
before performing the test.
3. While holding a thin strip of iron against the
armature in parallel with its axis, turn the armature
slowly. The armature is normal if the iron strip is
not attracted to the armature or it does not vibrate.
4. Check the insulation between commutator
segments and armature coils. The armature coils
are properly insulated if no continuity is present.
5. Check continuity between a segment and another.
There is no open circuit in the tested coil if there is
continuity.
MAGNETIC SWITCH
1. Coil open circuit test
•Check that there is continuity between the M
terminal and body A.
•If there is no continuity, replace the magnetic
switch.
2. Contact fusion check
•Check that there is no continuity between the B
terminal and M terminal.
•If there is continuity, replace the magnetic switch.
3. Switch contact check
•Push the indicated end of the magnetic switch
with a strong force to close the internal contacts.
Without releasing the switch end, check that
there is continuity between the B terminal and M
terminal.
•If there is no continuity, replace the magnetic
switch.
AK202733
Growler
AB
AK202734
AK202713
AK202891
A
M terminal
AB
AK202892
M terminal B terminal
AB
AK202893
M terminal B terminal
AB
Page 94 of 788
Page 95 of 788
IGNITION SYSTEM
ENGINE ELECTRICAL16-31
IGNITION COIL SPECIFICATION
SPARK PLUG SPECIFICATIONS
SERVICE SPECIFICATIONS
M1163000300180
IGNITION COIL
SPARK PLUG
RESISTIVE CORD
SPECIAL TOOL
M1163000600288
Item Specification
Type Molded 2-coil
Items 4G1 4G66
NGK BKR6E-11 IGR6A11
DENSO K20PR-U11
−
CHAMPION RC8YC4
−
Item Standard value
Secondary coil resistance kΩ8.5 − 11 . 5
ItemsStandard value Limit
Spark plug gap mm 4G1 1.0 − 1.1
−
4G6 1.0 − 1.1 1.3
Item Standard value Limit
Resistance kΩ
−Maximum 19
Tool Number Name Use
MD998773 Detonation sensor
wrenchDetonation sensor
removal and installation