Vanguard BIG BLOCK M540000, Repair Manual, Page: 36 / 168

Electrical Systems Alternator
System Diagnosis - Alternator
The troubleshooting guide that follows is designed to outline common problems, potential causes, and repair action related to
the alternator system. This guide is applicable to both carbureted and fuel-injected engines.
Alternator System Troubleshooting
Alternator System Troubleshooting
Problem Potential Cause Action
Engine RPM too low Check and adjust engine speed.
Check engine for excessive load.
Inline fuse blown (if equipped) Check fuse, replace if necessary.
Defective battery Test battery. See Test Battery .
Loose, pinched, or corroded battery ground leads Inspect battery ground leads. Test,
clean, or replace if necessary.
Loose, pinched, or corroded battery charge leads Inspect battery charge leads. Test,
clean, or replace if necessary.
Open, shorted, or grounded wires
between output connector and battery
Test wiring. Repair or replace if necessary.
Defective or improperly
grounded regulator-rectifier
Test regulator-rectifier and ground.
Repair or replace if necessary.
Damaged battery Inspect and test battery. See Test
Battery . Replace if necessary.
Excessive current draw from accessories Check current draw, turn off or disconnect
accessories, test accessories for excessive draw.
Battery not charging
Low magnetic flux or
damaged alternator magnets
Inspect components. Replace if necessary.
Mismatched battery to alternator output Check equipment operator's manual
for correct battery specifications.
Damaged battery Inspect and test battery. See Test Battery .
Battery overcharged
Defective regulator Test regulator. Replace if necessary.
Inline fuse blown Inspect and test fuse. Replace if necessary.
Defective auxiliary accessories
or auxiliary equipment
Inspect and test equipment.
Repair or replace if necessary.
Loose or corroded wires Inspect and test wiring. Repair
or replace if necessary.
Open, shorted or grounded wires between
output connector and accessories
Inspect and test wiring. Repair
or replace if necessary.
Accessories or auxiliary
equipment not working
Accessory or auxiliary equipment switch defective Test switch. Replace if necessary.
Charging System Identification
The alternator systems installed on Briggs & Stratton Model
540000 and 610000 OHV V-Twin engines can be identified
by the number of stator output wires OR by the voltage
regulator style.
Alternator Type Stator
Output Wires
Alternator
Output (at
3600 RPM)
Regulated 20 Amp 1 - Connector,
2 - Yellow Wires
1 - 20 DC Amps,
30 AC Volts
Regulated 20/50 Amp 2 - Connectors,
4 - Yellow Wires
3 - 50 DC Amps,
45 - 50 AC Volts
Regulator Type Regulator Wires Notes
20 Amp 2 - Yellow, 1 - Red
20/50 Amp 4 - Yellow, 1 - Red 20/50 Amp regulator
will have an inline fuse
on the red wire and
a capacitor mounted
to the top regulator
mounting bracket.
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