MERCURY ANODE 47820

Function and technical context

The Mercury 47820 sacrificial anode is a cathodic protection component designed for Mercury 20 hp engines operating in salt water. This element erodes in a controlled manner instead of the hull and metal parts of the engine, avoiding the galvanic corrosion that occurs when different metals come into contact with seawater. Its function is fundamental in the system of preserving the structural integrity of the engine, ensuring that electrochemical degradation is limited to the sacrificial anode and does not affect critical components such as cylinder heads, cooling pipes or the engine casing.

When to replace this part?

The Mercury 47820 anode requires regular inspection at the end of each boating season, especially after intensive use in salt water, as its wear depends on the type of water, salinity and hours of operation. Symptoms that it needs replacement include visible material loss, accelerated erosion, or white deposits forming around the installation area. Preventative replacement at the start of each season or after 100-150 hours of saltwater boating is the recommended practice to prevent galvanic corrosion from attacking expensive engine components; A worn anode is ineffective and exposes the motor to serious breakdowns.

Equivalent manufacturer part numbers