Yamaha - Water Pump Flange Cooling System Component YF1-58527-35-23. Overview. When you're working on Yamaha cooling systems, it's usually the smaller mounting and sealing parts that end up causing problems if they're worn. I've seen water pumps lose efficiency just because a flange wasn't holding everything tight and aligned. The Yamaha Water Pump Flange YF1-58527-35-23 helps secure the pump assembly so water moves the way it should. It's one of those parts that keeps the whole system working p