Yamaha - Impeller Water Pump Component 6H4-JD000-08-22. Overview. If there's one part I never ignore during service, it's the impeller. It's the heart of your cooling system, and once it starts to wear, everything else is at risk. I've seen engines overheat just from a worn set of blades that couldn't push enough water. Swap it out in time, and you keep your motor running cool and reliable every trip out.. Key Features. Efficient Water Circulation - Moves cooling water through the engine to maintain safe operating temperatures.. Flexible Blade Design - Blades flex and recover to maintain consistent water flow under load.. Heat-Resistant Rubber - Built to handle constant rotation, friction, and temperature changes.. Factory-Spec Fitment - Matches Yamaha pump housings for proper sealing and performance.. Critical Cooling Support - Helps prevent overheating and protects internal engine components.. Engine & Boat Compatibility. Designed for Yamaha outboard engines with compatible water pum