Corrosion Protection; Corrosion Information; Maintaining Ground Circuit Continuity; Sterndrive Corrosion Protection Components - Mercury 4.3 MPI SeaCore Operation & Maintenance Manual

Section 4 - Maintenance

Corrosion Protection

Corrosion Information

Whenever two or more dissimilar metals are submerged in a conductive solution, such as saltwater, polluted water or water
with a high mineral content, a chemical reaction takes place causing electrical current to flow between metals. The electrical
current flow causes the metal that is most chemically active, or anodic, to erode. This is known as galvanic corrosion. For more
information contact your authorized Mercury MerCruiser dealer.

Maintaining Ground Circuit Continuity

The transom assembly and sterndrive are equipped with a ground wire circuit to ensure good electrical continuity between the
engine, transom assembly, and sterndrive components. Good continuity is essential for the MerCathode System to function
effectively.

Sterndrive Corrosion Protection Components

To help control the effects of galvanic corrosion, sterndrives come with several sacrificial anodes and other corrosion protection
devices. For a more comprehensive explanation of corrosion and corrosion protection, refer to the Marine Corrosion
Protection Guide.
a
b
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f
a
b
c
f
a
b
c
e
c
d
Typical single sterndrive
a - Anode (Alpha models), MerCathode (Bravo models)
b - Ventilation plate anode
c - Trim cylinder anodes
d - Bearing carrier anodes
e - Gearcase anodic plate
f - Anode kit on hull (if equipped)
e
d
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Dual sterndrive
a - Anode (Alpha models), MerCathode (Bravo models)
b - Ventilation plate anode
c - Trim cylinder anodes
d - Bearing carrier anodes
e - Gearcase anodic plate
f - Anode kit on hull (if equipped)
e
d
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90-8M0113859 DECEMBER 2015
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