Transon OMC Aluminum Anode

Function and Technical Context

The aluminum sacrificial anode for OMC transom acts as galvanic protection in the stern area, absorbing the electrochemical corrosion that would otherwise attack the metal parts of the outboard motor and the hull itself. Located on the transom, this element is the first to degrade in a controlled manner when the metal assembly is exposed to salt water, brackish water, or even fresh water with high mineral content. Without sound anodic protection, components such as the gearbox, propeller, shaft, and mounting hardware are exposed to accelerated corrosion, which can result in serious structural damage and costly repairs. The aluminum used in this anode offers electrochemical performance especially suited for salt and brackish waters, surpassing zinc in these environments in terms of active protection potential. It replaces OMC references 983952 and 984547, corresponding to the current reference CM984547A.

When to Replace This Part?

The clearest sign that the anode needs to be changed is the loss of more than 50% of its mass: when the aluminum material has been consumed to half or cracks and surface fragmentation appear, the galvanic protection is no longer effective. Inspection and replacement are recommended at least once per season, coinciding with annual haul-out or with each preventive maintenance intervention of the motor. Changing the anode preventively is the most economical measure to avoid corrosion of high-cost parts such as the leg, propeller shaft, or mounting hardware on the transom.

Compatible Johnson/Evinrude Motors

Equivalent Manufacturer References