MERCURY IMPELLER 47-19453T

Function and technical context

The impeller is the critical component of the outboard motor's water cooling system. Its mission is to pump water into the cooling gallery to keep the engine at safe operating temperature, especially on saltwater boats where overheating represents a serious risk. This flexible rubber impeller generates the necessary flow when coupled with the transmission shaft, guaranteeing constant circulation that prevents excessive heating of the engine block and internal corrosion. Without an impeller in good condition, the motor loses thermal dissipation capacity and is at risk of mechanical seizure.

When to replace this part?

The impeller should be replaced when loss of flexibility in the blades, hardening of the rubber, partial breaks are observed, or when the engine begins to operate at abnormally high temperatures at full load. Visual inspection is recommended every season and preventive replacement every 300-400 hours of operation or every two years if the engine is used in salt water, where corrosion accelerates wear. Replacing the impeller preventively is the most economical measure to avoid costly repairs resulting from overheating.

Engine Compatibility

Compatible Mercury Mariner Engines

Equivalent manufacturer part numbers