ARO 93210-66M98 REC93210-66M98

Function and technical context

This ring is part of the sealing and watertight system in Yamaha and Mercury marine engines, acting as a retaining element in critical areas of the engine where a hermetic barrier between components is required. Its function is essential to prevent water, oil or coolant leaks that could compromise the integrity of the engine and cause internal corrosion. It works integrated into the structure of the engine block, supporting variable pressures and temperatures typical of operation in saline marine environments. Failure or wear in this part allows seawater to enter internal areas, accelerating the oxidation of metals and causing progressive damage that is difficult to detect until it is too late.

When to replace this part?

This type of ring should be inspected annually before each boating season and checked after beachings or repairs where the engine has been removed. Symptoms of degradation include the presence of water in the crankcase, moisture stains around the joints, accelerated surface corrosion or gradual loss of tightness in specific areas of the block. Preventively replacing this component during scheduled maintenance is much more economical than repairing damage due to salt water infiltration, which can affect cylinders, pistons and engine lubrication systems.

Equivalent manufacturer part numbers