OMC Cobra 5700 Anode

Function and Technical Context

This sacrificial anode is designed to protect the front casing of the gear housing in OMC Cobra outboard engines, acting as a galvanic element that preferentially corrodes rather than the structural metal parts of the propulsion unit. Its function is to absorb the electrochemical corrosion generated when the engine is submerged in saltwater or brackish water, protecting critical components such as the shaft housing, propeller hub, and transmission elements of the lower propulsion unit. If this anode is depleted without being replaced in time, galvanic corrosion directly attacks the aluminum and steel parts of the gear housing, potentially causing irreversible damage to the transmission and propeller housing. It corresponds to OMC references 3854061 and 987067 (alternative reference 0987067 → 3854061), approved for use in Johnson and Evinrude product lines.

When to Replace This Part?

The most obvious symptom that the anode has reached the end of its service life is a reduction in mass of more than 50%, visually apparent as a heavily worn, irregular, or nearly nonexistent part; at that point it has ceased to effectively protect the engine. It is recommended to inspect and replace sacrificial anodes at least once per season, or more frequently if the vessel normally operates in waters with high salinity or elevated conductivity. Preventively changing the anode at the beginning of each season is the most economical measure to avoid costly repairs to the propulsion unit, especially in mooring areas with stray electrical current.

Compatible Johnson/Evinrude Engines

Equivalent Manufacturer References