TESTING AND ADJUSTING
1. Voltage adjustment cap.
Cables between the battery, starter and engine
ground must be the correct size. Wires and
cables must be free of corrosion and have cable
No adjustment can be made to change the rate
support clamps to prevent stress on battery
of charge on these alternator regulators. If the rate of
charge (ampere output) is within 10 amperes of rated
output (marked on the alternator frame) the regulator is
good. An over or under charged battery condition can be
instruments that have direct relation to the
corrected sometimes by an adjustment to the voltage. If
charging circuit must give correct circuit control.
rate of charge is not correct, a replacement of the
regulator is necessary.
Inspect the drive components for the charging
unit to be sure they are free of grease and oil
Alternator Pulley Nut Tightening
and have the ability to operate the charging unit.
Tighten nut that holds the pulley to a torque of 100 10
Alternator Regulator Adjustment
Nm (75 Z 5 lb. ft.) with the tools shown.
When an alternator is charging the battery too
much or not enough, an adjustment can be made to the
output voltage of some alternators. Make reference to
the SPECIFICATIONS section to find all testing
specifications for the alternators and regulators.
Delco-Remy 24V 60A (4N3986 Alternator)
No adjustment of voltage output can be made on
this alternator. If the voltage and ampere output is not
correct, the alternator must be repaired or replaced.
Delco-Remy 32V 60A (4N3987 Alternator)
To make an adjustment to the voltage output,
pull out voltage adjustment cap (1). Turn the cap 90
TOOLS TO TIGHTEN ALTERNATOR PULLEY NUT
and install it again into the alternator. The voltage
1. 5P7425 Torque Wrench. 2. 8S1588 Adapter (1/2"
adjustment cap has four positions: HI, LO, and two
female to 3/8" male). 3. FT1697 Socket. 4. 8H8517
positions between the high and the low setting.
Combination Wrench (1 1/8"). 5. FT1696 Wrench.
The 4N3987 Alternator can be adjusted for either
30 or 32 volts. A replacement alternator shipped from
the factory will be adjusted for 32V (16 battery cells)
systems. Where the alternator is to be used in a 30V (15
Use the multimeter in the DCV range to find
battery cells) system, pull out voltage adjustment cap (1)
starting system components which do not function.
and change from the HI position to position 3.
Move the start control switch to activate the
starter solenoid. Starter solenoid operation can be heard
as the pinion of the starter motor is engaged with the ring
gear on the engine flywheel.
If the solenoid for the starter motor will not
operate, it is possible that the current from the battery did
not get to the solenoid. Fasten one lead of the
multimeter to the connection (terminal) for the battery
cable on the solenoid. Put the other lead to a good
ground. A zero reading is an indication that there is a
broken circuit from the battery.
More testing is
necessary when there is a voltage reading on the
CAP TYPE REGULATOR ADJUSTMENT