Yamaha - Water Pump Adapter Cooling System Component 6H4-JD009-06-00. Overview. When you're working on the water pump, the adapter is one of those pieces that has to be right or nothing lines up the way it should. I've run into setups where a worn or damaged adapter caused poor sealing or uneven water flow, and it doesn't take long before cooling performance drops off. This is the kind of part that keeps everything in the pump assembly properly seated and flowing. Get it right, and the whole cooling system works the way it's supposed to.. Key Features. Proper Pump Alignment - Ensures correct positioning of water pump components for efficient operation.. Consistent Water Flow Support - Helps maintain smooth and uninterrupted cooling water movement.. Durable Construction - Built to withstand heat, pressure, and constant water exposure.. Factory-Spec Fitment - Designed for precise integration with Yamaha cooling systems.. Reliable Sealing Surface - Supports tight connections to prevent le