Yamaha - Water Pump Housing Cooling System 6AW-44311-01-00. Overview. The water pump housing is the foundation of the entire cooling pump assembly. The Yamaha 6AW-44311-01-00 Water Pump Housing surrounds the impeller and forms the chamber that allows water to be drawn up from the lower unit and circulated through the engine. Over time, sand, debris, and impeller wear can score or damage the housing surface, reducing pump efficiency. Replacing a worn housing during pump service helps restore proper cooling performance and keeps large Yamaha offshore engines running at safe operating temperatures.. Key Features. • Impeller Chamber Housing - Provides the internal cavity where the impeller spins to move cooling water through the engine.. • Restores Water Pump Efficiency - Replacing worn housings helps maintain proper cooling water flow and pump pressure.. • OEM Yamaha Construction - Manufactured to Yamaha specifications for correct fit and reliable operation.. • Ideal During Pump Rebuilds