Mercury MerCruiser Alpha - Service Manual

2002-06 APRIL 2002 Printed in U.S.A. -  2002, Mercury Marine Page 1 of 16
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This document is provided for the sole and exclusive use of the original recipient as prescribed by Mercury Marine and may not be distributed or
copied, digitally or otherwise, without the prior written consent of Mercury Marine.
Bulletin No. 2002-06
WARRANTY INFORMATION SERVICE INFORMATION
PARTS INFORMATION
Sales ManagerCirculate to: Accounting Service Manager Technician Parts Manager
Corrosion Prevention and Maintenance
Models
ALL MerCruiser, Outboard and Jet Drive Products
Drive Corrosion
The prevention of marine corrosion can be a challenge for boat owners. However, corrosion
damage is almost always controllable; it just requires knowledge of what causes corrosion,
and the proper maintenance steps that must be taken to protect the product.
Over the years, Mercury has published several guides and manuals to educate dealers and
boat owners about corrosion, and what steps should be taken to prevent corrosion from
causing significant and costly damage to submerged drive components. All Mercury dealers
should be familiar with these publications, understand the primary causes of corrosion, and
what to do to prevent marine corrosion in all types of boating environments. During the pre-
delivery inspection process with the boat owner, review the proper maintenance activities
that are needed to ensure that the boat and sterndrive are properly protected from corrosion.
Also, we encourage you to review the contents of the Mercury Corrosion Protection Guide
with them, and give them a copy to take home. This guide is available to you at no charge
by ordering 90-881813 01 (Mercury branding) or 90-809844 01 (Quicksilver branding).
If a boat owner has a complaint about corrosion damage, please perform the necessary in-
spection and testing procedures to identify the source of the corrosion (see enclosed 3 page
Corrosion Test Data Sheet that can assist you in this effort). As always, our dealer technical
support team is available to provide technical assistance in the diagnosis and correction of
corrosion. Contact MerCruiser technical support at 405-743-6555 or outboard technical
support at 920-929-5884.

Summary

Corrosion Prevention and Maintenance

Models

Lists all affected MerCruiser, Outboard and Jet Drive models covered by the bulletin.

Drive Corrosion

Discusses the challenges and importance of preventing drive corrosion for boat owners.

What is Corrosion

Galvanic Corrosion

Explains electrochemical reaction between dissimilar metals in a conductive solution.

Stray Current Corrosion

Describes corrosion caused by leakage of current to ground, often from shore power.

Corrosion Protection Methods

Sacrificial Anodes

Anodes made of aluminum or magnesium to prevent corrosion in different water types.

MerCathode

Standard or kit system for anodic protection on Bravo and Alpha products.

Transom Mounted Anode

Anode connected to MerCathode for additional protection.

Transom Mounted MerCathode Kit

Kit for Outboards, Jet Drive, and older MerCruiser without Gimbal housing access.

Defender Anode

Connects to battery or engine ground for protection while the boat is moored.

Galvanic Isolator

Filters DC currents to prevent galvanic corrosion while maintaining safety grounding.

Test Equipment

Corrosion Information Publications

Detailed Corrosion Testing Procedures

Tools Required

Lists necessary tools for performing corrosion tests.

Pre-test Checks

Initial checks before starting corrosion testing procedures.

Preparing for Testing

Boat mooring requirement for at least eight hours before testing.

Conductivity Check

Method for checking conductivity using a multimeter and reference electrode.

Measuring Hull Potential

Procedure for measuring hull potential using multimeter and reference electrode.

Hull Potential Readings Interpretation

Defines low, high, and proper hull potential readings for different water types.

Troubleshooting Low Hull Potential

Identifies causes and testing for low hull potential readings.

Troubleshooting High Hull Potential

Identifies causes and testing for high hull potential readings.

Faulty MerCathode Controller Testing

Procedures to check the MerCathode controller's output and functionality.

Checking MerCathode Anode Output

Method to measure the output of the MerCathode anode using a multimeter.

Out of Water Resistance Check

Galvanic Isolator Testing

Anode Kits for MerCruiser Sterndrives

Corrosion Test Data Sheet

Continuity Test Procedure

Mercury MerCruiser Alpha Specifications

General

Brand	Mercury MerCruiser
Model	Alpha
Category	Outboard Motor
Language	English