IMPELLER 47-20813 REC47-20813

Function and technical context

The impeller is the central component of the water cooling system of Mercury, Mariner and Mercruiser engines. This piece acts as a circulation pump, driving cooling water from the inlet to the internal ducts of the engine to dissipate the heat generated during combustion. Its correct operation is critical to maintain engine temperature within safe ranges; A worn or damaged impeller significantly reduces the water flow, causing progressive overheating that can lead to serious engine breakdowns, accelerated internal corrosion and, in extreme cases, impeller seizure.

When to replace this part?

Impellers gradually wear out from abrasion caused by water, sand particles and corrosion, especially in saltwater use. Typical symptoms include engine overheating even at moderate speeds, reduced water flow at the cooling outlet, and decreased power. It is recommended to inspect the impeller every navigation season and replace it preventively every 300-400 hours of operation or when signs of visible wear are detected on its blades. Preventive replacement is especially important before long voyages, as it avoids costly emergency repairs at sea and significantly extends engine life.

Equivalent manufacturer part numbers