NOTE: Proper tension is a measurement of deflection with moderate thumb pressure on the belt at the location that has
the longest distance between two pulleys.
Description
Deflection
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.
MerCathode System Battery Requirements
The Mercury MerCruiser MerCathode system requires a minimum battery charge of 12.6 volts at all times to maintain
functionality.
Boats equipped with a MerCathode system that use shore power, and are not run for a long period of time, must use a battery
charger to maintain a minimum battery charge of 12.6 volts or above.
Boats equipped with a MerCathode system that do not have access to shore power must be operated often enough to maintain
a minimum battery charge of 12.6 volts or above at all times.
MerCathode Theory of Operation
The MerCathode system provides corrosion protection by impressing a reverse blocking current that stops the destructive flow
of galvanic currents. The MerCathode controller will regulate output to maintain 0.94 volts at the reference electrode.
90-8M0128976
MAY 2017
eng
Deflection measurement point
Section 4 - Maintenance
50920
13 mm (½ in.)
Page 71