Yamaha - Water Tube 1 Cooling System Component 6C5-44361-10-00. Overview. Cooling flow is something you don't think about until the engine starts running hot. This water tube is what carries cooling water from the lower unit up into the powerhead, and if it's restricted or out of place, the whole system struggles. I've seen overheating issues come down to something as simple as a damaged or misaligned tube. Keeping this path clear is key to keeping the motor running cool and steady.. Key Features. • Direct Cooling Water Transfer - Moves water efficiently from the pump to the engine.. • Maintains Engine Temperature - Supports proper cooling under load and extended use.. • OEM Fit Accuracy - Matches Yamaha factory specs for correct alignment and installation.. • Durable Marine Construction - Built to handle heat, pressure, and harsh water conditions.. Engine & Boat Compatibility. Verify compatibility with your specific Yamaha outboard model and part number before installation.. FAQs. Q1: