Open Regulator Test - MerCruiser GM4 Service Manual

OPEN REGULATOR TEST

IMPORTANT: This test requires removal of regu-
lator.
! CAUTION
To prevent electrical system damage and/or
sparks, disconnect battery cables at battery.
1. Remove insulator cap from regulator terminal.
2. With ignition switch on and engine not running,
check for battery voltage at alternator output ter-
minal (Test 1) and regulator terminal (Test 2).
a
b
a - Regulator Terminal
b - Output Terminal
c - Ground
d - Voltmeter (0-20 Volts)
3. Remove the four screws which secure the regula-
tor to the alternator.
Index
4C - 26 - CHARGING SYSTEM
c
d
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4. Connect a jumper wire between field terminal
(GREEN WIRE) and ground/ If 1.5 to 3.0 volts are
present at regulator terminal, regulator is defec-
tive. If voltage is not present at regulator terminal,
there is an open field circuit (brushes slip rings,
etc.). Remove alternator for repair.
a
b
a - Field Terminal (GREEN WIRE)
b - Regulator Terminal
c - Ground
d - Voltmeter (0-20 Volts)
NOTE: Felt gasket shown removed for visual clarity.
d
c
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90-816462 2-695