Yamaha - Water Pump Repair Kit Cooling System Service 6H3-W0078-A0-00. Overview. If you're running an older Yamaha, especially one that's seen a lot of water time, staying ahead of the cooling system is key. I've worked on plenty where the pump was just tired-nothing catastrophic, just worn enough to cause weak flow and rising temps. This kind of full kit takes the guesswork out and lets you rebuild it properly in one go. Once it's done right, you know you can trust it every time you fire up the