Figure 3-12. Voltage regulator adjustment circuit.
cover and screws. Reconnect the field, and operate for
(2) Operate the engine at fast idle (700 to
no more than 5 minutes to ensure that you have
1000 rpm) to stabilize the electrical system until the
obtained the desired change in voltage.
voltmeter stops showing a charge. This should occur
between 5 to 15 minutes.
3-19. Starting Motor
(3) Leave the engine running and remove
bakelite covered field connector on back of alternator.
Remove the four cover screws and remove cover from
voltage regulator. Reconnect the field to the alternator.
Disconnect the battery cable from the
disconnecting any other electrical leads
from the engine components. This will
The variable voltage control is connected
prevent shorts which could damage the
to alternator output and is electrically hot.
alternator, voltage regulator, and other
Do not let adjustment tool touch anything
but voltage control.
Removal. Remove the starting motor (TM 5-
(4) Use a No. 2 Phillips screwdriver to
4320-12, para 4-42).
adjust the voltage control. Turn the control a few
degrees counterclockwise if you want to reduce voltage,
Pinion Clearance Check. After removing the
or turn it clockwise to increase voltage. Stops are
starting motor, check pinion clearance. The clearance
provided in the control to limit rotation to less than 1/2
cannot be adjusted, but improper clearance will indicate
turn total. Do not try to force control beyond stops.
worn parts and the need for starting motor replacement.
To check the pinion clearance, refer to figure 3-13 and
proceed as follows:
connector on back of alternator. Reinstall the regulator