IMPELLER COVER 66T-44323-00 REC66T-44323-00

Function and technical context

The impeller cover is an essential component of the cooling circuit in Yamaha outboard engines. This part directly protects the water pump impeller, whose mission is to push the coolant fluid through the internal passages of the engine to maintain operating temperatures within safe ranges. The cover acts as a hermetic seal and mechanical shield, preventing sediment, algae remains and suspended particles from salt water from penetrating the impeller blades. A deterioration in the integrity of the cap seriously compromises the efficiency of the cooling system, exposing the engine to the risk of severe overheating and catastrophic failure of internal components.

When to replace this part?

The impeller and its cover suffer natural wear due to continuous contact with salt water and the abrasive flow of suspended particles. Common indicators of wear include visible water leaks in the coolant pump area, abnormal noises in the cooling system, or persistent high temperature readings on the instrument panel. A visual inspection of the impeller cover is recommended at the beginning of each boating season and its preventive replacement every 300 to 400 hours of operation, depending on the intensity of use and water conditions. Making a preventative change to your regular maintenance schedule avoids running out of cooling in open water, where emergency repairs are costly, difficult to execute, and potentially dangerous.

Engine Compatibility

Equivalent manufacturer part numbers