4C - 14 - CHARGING SYSTEM
90-816462 2-695
d. If reading is low, a short exists in the field cir-
cuit. Inspect slip rings to be sure that they are
not bent and touching outer slip ring. Also, be
sure that excess solder is not shorting termi-
nals to aft slip ring. If cause for short cannot
be found, unsolder field winding leads from
slip ring terminals and connect ohmmeter di-
rectly to leads. If correct reading is now ob-
tained, or if reading is still low, slip rings and
rotor field windings are shorted, and complete
rotor assembly must be replaced.
73112
b
c
d
a
a - Field Winding Leads
b - Slip Rings
c - Rotor Shaft
d - Pole Pieces
2. Test rotor field circuit for grounds (Test 2), using
an ohmmeter (set on R x1 scale) as follows:
a. Connect one lead of ohmmeter to either slip
ring and the other lead to rotor shaft or pole
pieces.
b. Meter should indicate no continuity (meter
should not move).
c. If continuity does exist, complete rotor assem-
bly must be replaced.
IMPORTANT: If alternator has output at low
speeds, but no output at high speeds, rotor field
winding may be shorting or grounding out, due to
centrifugal force. Replace rotor if all other electri-
cal components test good.
STATOR
IMPORTANT: Stator leads MUST BE discon-
nected from rectifier for this test.
1. Test stator for grounds (Test 1), using an ohmme-
ter (set on R x1 scale) as follows:
a. Connect one lead of ohmmeter to one of the
stator leads and the other lead to stator frame.
Be sure that lead makes good contact with
frame.
b. Meter should indicate no continuity (meter
should not move). If continuity does exist, sta-
tor is grounded and must be replaced.
2. Test for opens in stator (Test 2), using an ohmme-
ter (set on R x1 scale) as follows:
a. Connect ohmmeter between each pair of sta-
tor windings (three different ways).
b. Continuity should be present in all three cases
(meter should move). If it does not, one or
more of the windings are open and stator
must be replaced.
72833
TEST 1
TEST 2
TEST 2
TEST 2
Testing Stator
3. A short in the stator is difficult to detect without
special equipment, because of the low windings
resistance. If all other electrical components test
out good, and alternator fails to produce rated
output, stator probably is shorted and should be
replaced. Also, examine stator for heat discolor-
ation, as this usually is a sure sign of a short.
Summary of Contents for 13
Page 1: ...13 Printed in U S A 90 816462 2 695 1995 Brunswick Corporation GM 4 Cylinder MARINE ENGINES ...
Page 2: ...90 816462 2 695 0 ...
Page 7: ...1 A IMPORTANT INFORMATION GENERAL INFORMATION 72000 ...
Page 15: ...1 B 50617 IMPORTANT INFORMATION MAINTENANCE ...
Page 36: ...1 C IMPORTANT INFORMATION TROUBLESHOOTING ...
Page 74: ...2 A 50633 REMOVAL AND INSTALLATION 4 CYL ALPHA ONE DRIVE ...
Page 88: ...3 A 26790 ENGINE 181 CID 3 0L 4 CYLINDER GM ENGINE ...
Page 137: ...4 A 72079 ELECTRICAL SYSTEMS STARTING SYSTEM ...
Page 170: ...4 B 71855 ELECTRICAL SYSTEMS IGNITION SYSTEM ...
Page 197: ...ELECTRICAL SYSTEMS CHARGING SYSTEM 4 C 72078 ...
Page 237: ...4 D 72747 ELECTRICAL SYSTEMS INSTRUMENTATION ...
Page 250: ...4 E 72938 ELECTRICAL SYSTEMS WIRING DIAGRAMS ...
Page 264: ...5 A FUEL SYSTEM FUEL PUMP ...
Page 271: ...5 B 72681 FUEL SYSTEM MERCARB 2 BARREL CARBURETOR ...
Page 300: ...6 A 50628 COOLING SYSTEM SEAWATER COOLED MODELS ...
Page 309: ...6 B 73665 COOLING SYSTEM CLOSED COOLING MODELS ...
Page 325: ...C 6 EXHAUST SYSTEM MANIFOLD ...
Page 331: ...7 A 71317 POWER STEERING PUMP ...