Yamaha - Water Cover Cooling System Component YF1-43847-22-90. Overview. Cooling issues on a Yamaha don't always come from big failures-sometimes it's something simple like a cover not sealing right. I've seen engines lose efficiency just from minor leaks or warped covers that throw off water flow. The Yamaha Water Cover YF1-43847-22-90 helps keep the cooling system sealed so everything moves the way it should. It's a small part, but it keeps the whole system working smoothly.. Key Features. • Seals Cooling System Pathways - Helps maintain proper water pressure and flow within the engine.. • Yamaha Engineered Fit - Built to factory specs for accurate alignment and sealing.. • Durable Construction - Designed to handle heat, water exposure, and engine vibration.. • Supports Cooling Performance - Keeps internal passages sealed to prevent leaks and inefficiency.. • Direct Replacement Component - Installs in place of the original cover during service or repair.. Engine & Boat Compatibility.