Mercury Racing HP525 EFI Bravo Sterndrive Series, Operation, Maintenance & Warranty Manual

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MAINTENANCE
108
eng
Corrosion and Corrosion Protection
Whenever two or more dissimilar metals (like those found on the
sterndrive) 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 corrode. This is known as
galvanic corrosion and, if not controlled, it will in time cause the
need for replacement of power package components exposed to
water.
Refer to the Quicksilver booklet,
Everything You Need to Know
About Marine Corrosion
for more corrosion information.
NOTICE
Using magnesium anodes in salt water causes an
electrochemical reaction on the metal surface of the drive,
resulting in corrosion damage from the paint blistering and
peeling off the drive. Use magnesium anodes in fresh water
only.
IMPORTANT: Mercury Marine recommends installing a
MerCathode System or Anti‑Corrosion Kit be installed whenever
using a stainless steel propeller, or if the boat is equipped with
stainless steel components (immersed below the waterline) that
are connected into the engine ground system. If a boat is
equipped with stainless steel after planes, a large anode should
be installed on each to handle the increased galvanic corrosion
potential.
Replace sacrificial anodes if eroded 50% or more.
Mercury Marine recommends using anodes sold through
Mercury Precision Parts only. Some other manufacturers of
aluminum anodes use alloys that are insufficiently pure to
adequately protect critical drive components for the duration of
the anodes' expected life.
MERCATHODE SYSTEM
The MerCathode System should be tested to ensure adequate
output.