Yamaha - Water Pump Repair Kit Cooling System Service Kit 6F5-W0078-A0-00. Overview. The Yamaha Water Pump Repair Kit 6F5-W0078-A0-00 is one of those must-have kits when you're keeping an older two-stroke running right. On engines like the CV40, cooling issues can show up fast if the pump starts to wear out. This kit gives you everything you need to refresh the system and get water flow back where it should be. If you're dealing with weak pressure or just doing routine service, this is the kind of maintenance that saves engines.. Key Features. • Complete Pump Rebuild Kit - Includes essential components for restoring water pump performance.. • OEM Fit Precision - Built to Yamaha specifications for proper alignment and reliable installation.. • Restores Cooling Flow - Helps bring back strong water circulation and stable engine temperatures.. • Durable Marine Components - Designed to handle heat, friction, and continuous water exposure.. Engine & Boat Compatibility. • CV40 1990. FAQs. Q1: