Starting
System
These models use a separate
12
volt starting motor
mounted on the right hand side of the engine to drive
the flywheel.
It
is a standard automotive starting
motor with a solenoid for engaging the pinion and an
over-running clutch.
When
the solenoid is energized,
its core pulls in, shifting the pinion into engagement
with the flywheel ring gear.
At
the same time, con-
tacts in the solenoid close to provide a circuit for the
starter motor. The starting motor remains engaged
until the starting switch
is
released.
If
engine
is
equipped with a start-disconnect switch, the starter
motor will automatically disengage flywheel gear when engine
speed reaches
about
900
rpm.
The starter is protected from over-speed by an over-
running clutch which permits theengine to run faster
than the starter before
the
pinion
is
disengaged. Fig-
ure
86
shows the starting circuit.
MAlNTENANCE
Periodically check thestarting circuitwiring for loose
or dirty connections. Inspect the starter commutator,
and if it is dirty, clean with number
00
sandpaper (do
not use emery cloth or emery paper). Check the
brushes for poor seating
on
the commutator and for
excessive wear.
TESTING
Poor cranking performance can be caused by afaulty
starting motor, defective battery, or high resistance in
the starting circuit.
Check the charge condition of the battery with a
hydrometer.
Ignition
of
explosive battery gases
might cause severe personal injury.
Do
not
smoke while servicing batteries.
Specific gravity should be between
1.290
and
1.225
when
75
percent charged. If not, recharge the battery.
Check electrolyte level. If battery will not recharge,
replace
it.
Keep battery connections tight and clean.
With the starting motor operating, check the voltage
drops
(1) from the battery ground terminal post (not
the cable clamp) to the cylinder block,
(2)
from the
cylinder block to the starting motor frame and
(3)
from
the
battery positive post to the battery terminal
stud on the solenoid. Normally, the voltage drops at
(1)
and
(3)
should never exceed
0.6
V
each, even
underthe most severeconditions (extremecold).The
voltage drop at
(2)
should never be permitted to
exceed
0.3
V
under
the
same severe conditions. Tho-
roughly clean all connections
in
any part of the circuit
showing excesively high voltage drops.
If starting motor tests are required, remove the motor
from the engine and test it on a bench. Test the free-
running voltage and current.
TO
START SOLENOID
PSTARTl
NG
L.
I-
I
SOLENOID
/r
GROUND CONNECTION
TO ENGINE
nnnnn
FIGURE
86.
STARTING
SYSTEM
Using a spring scale and torque arm, test the stall
torque, Figure
87.
Multiply the spring scale reading
by the arm length for the torque valve.
If free running speed is
low, and starter has a high
current draw with low stall torque, check for tight,
dirty or Worn bushings, bent armature shaft, or loose
field pole screws, allowing armature to drag. Check
also for shorted or grounded armature and field.
A
low free speed with low torque and
low
current
draw indicates an open field winding, high internal
resistance due to poor connections, defective leads,
broken or worn brushes, or scored, worn, or dirty
commutator.
Redistribution or publication of this document,
by any means, is strictly prohibited.
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