MERCURY TAIL ANODE 822777Q1

Function and technical context

The tail anode is a passive cathodic protection component installed in the aft area of Mercury, Mariner and MerCruiser outboard motors and propulsion units. Its function is to electrochemically sacrifice itself to protect metal engine parts against galvanic corrosion in salt water environments. Being made of aluminum, it acts as a more active metal than the steel and iron of the engine, attracting corrosive ions and preventing them from attacking critical structural components such as the aft flange, bushings and the internal surfaces of the housing. Without preventive maintenance of this anode, corrosion quickly penetrates seawater, compromising the tightness of the engine and accelerating the failure of internal components.

When to replace this part?

The tail anode should be inspected each boating season and replaced when it shows advanced corrosion, visible erosion, or greater than 50% material loss. In saltwater with regular navigation, the typical lifespan is one full season. If you detect accelerated corrosion in other parts of the engine, whitish deposits or cracks in the anode, immediate replacement is a priority. Changing the anode preventively at the beginning of each nautical campaign is the recommended practice to avoid costly repairs and ensure engine longevity in demanding marine conditions.

Equivalent manufacturer part numbers