Yamaha Water Pump Impeller Cooling System Component 6CE-44352-00-00. Overview. Keeping a Yamaha outboard running cool starts with a healthy water pump, and the impeller is the heart of that system. This genuine Yamaha water pump impeller moves a steady flow of cooling water through the engine, helping prevent overheating during long runs or slow trolling days on the water. Whether you are running offshore, cruising the bay, or working the motor hard in summer heat, a dependable impeller keeps th