LOWER SEAL CRANKSHAFT YAMAHA 93102-30M23

Function and technical context

The lower crankshaft seal is a fundamental sealing piece in Yamaha engines that prevents oil leakage from the crankcase to the outside in the lower area of the crankshaft. This component works in the lubrication system, supporting constant engine oil pressure while maintaining airtightness between the engine block and the crankshaft. Its wear or deterioration allows the infiltration of salt water and the progressive loss of lubricant, compromising the integrity of the lubrication system and accelerating internal engine wear, especially critical in marine applications exposed to vibrations, pressure changes and constant thermal cycles.

When to replace this part?

Symptoms of failure include visible oil stains under the engine, loss of lubricant level without apparent cause, and the presence of water in the crankcase detected during oil changes. It is recommended to inspect the condition of the seal during each seasonal inspection and replace it preventively every 5-7 years or after hours of intense operation, especially if moisture in the oil or leaks is detected. The preventive change in dock avoids emergency repairs in navigation and significantly prolongs the useful life of the engine.

Equivalent manufacturer part numbers