TAIL SEAL KIT 26-66303A1

Function and technical context

Tail seals play a critical role in sealing the propulsion system, preventing salt water from entering the internal areas of the engine and gearbox. They work in the marine propulsion and transmission system, specifically at the interface between the propeller shaft and the engine casing. When these seals are worn or damaged, they allow water infiltration and corrosion that compromises the structural integrity of the drive assembly, potentially causing internal oxidation, loss of lubrication and catastrophic engine failure.

When to replace this part?

Symptoms of seal wear include water in the gearbox, oily grease stains around the drive shaft, visible corrosion in normally dry areas of the engine, and abnormal loss of lubricant in the transmission system. It is recommended to check the condition of the seals during each seasonal maintenance and replace the kit preventively every 300-400 hours of operation or when any sign of infiltration is detected. Performing this replacement preventatively is significantly more economical than repairing damage resulting from water ingress into the propulsion system.

Compatible Mercury Mariner Engines

Equivalent manufacturer part numbers