Yamaha - Chrome Water Pump Kit Cooling System Service 6H3-W0078-1B-00. Overview. When you're servicing a water pump, it's not just about swapping parts-it's about making sure the whole system is solid when you button it back up. I've used kits like this on motors that needed a full refresh, especially after running in salt or sandy water. If the pump isn't doing its job, everything else suffers fast. Getting it right here means you can run the motor hard without worrying about temperature creepi