LOWER SEAL CRANKSHAFT YAMAHA 93102-25M48

Function and technical context

The lower crankshaft seal is a critical component of the engine sealing system that prevents the leakage of lubricating oil from the crankshaft casing to the outside. Located at the bottom of the engine block, it hermetically seals the point where the crankshaft shaft passes through the lower cover, protecting it from the ingress of salt water and marine moisture. A failure in this seal compromises the internal lubrication of the engine and allows contamination of the oil by water, which accelerates the wear of bearings, gears and critical contact surfaces, which can lead to serious damage to the propeller.

When to replace this part?

The presence of oil under the engine, stains on the lower area of ​​the block or a characteristic smell of burnt lubricant are indicators of seal wear. Although there is no set maintenance interval, it is recommended that the condition of all crankshaft seals be inspected during each seasonal service, especially after extended periods of sailing or dry storage. Replacing this component preventively is an economical practice that avoids costly repairs resulting from engine oil contamination and damage to internal components.

Equivalent manufacturer part numbers