Voltage Regulator Test; Lamps Burn Out When Engine Rpm Is Increased; Lamps Burn Dim At Wide-Open-Throttle; Battery Charging System - Mercury 15XD Service Manual

Voltage Regulator Test

Lamps Burn Out When Engine RPM is Increased

The voltage regulator is defective. Replace regulator.

Lamps Burn Dim at Wide-Open-Throttle

1. Run engine at mid-range (approximately 3000 RPM) with 3 number 94 lamps con-
nected to voltage regulator output leads. Note lamp brightness.
2. Disconnect the leads at one terminal of regulator. Connect the leads together using
a screw and nut. Isolate (tape) connection.
3. Run engine at mid-range (approximately 3000 RPM) and note lamp brightness. If
lamps are considerably brighter than with leads connected to regulator, the regulator
is defective. If lamps are NOT considerably brighter, check the alternator (refer to "
Alternator Test" , following.

Battery Charging System

Description

The battery charging system components are the alternator, rectifier and battery. Alternat-
ing current (generated in alternator coils) flows to the rectifier which changes AC current
to direct current (DC) for charging the battery.
a -
b -
c -
The charging system may be damaged by:
a. Reversed battery cables.
b. Running the engine with battery cables disconnected and alternator leads con-
c. An open circuit -- such as a broken wire or loose connection.
90-826883R2 JUNE 1998
c
Alternator
Rectifier
Battery
nected to rectifier.
BATTERY CHARGING AND STARTING SYSTEMS
a
b
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