Yamaha - Water Tube 1 6FM-44361-10-00. Overview. The Yamaha Water Tube 1 6FM-44361-10-00 is one of those parts that quietly keeps your engine from running hot. When it starts to clog up or wear out, you'll notice it in weak water flow or rising temps, especially when idling or running slow. It routes cooling water where it needs to go inside the engine, so it has to stay clear and properly seated. If you're doing cooling system work or chasing overheating, this is a solid part to swap out.. Key Features. • Efficient Water Routing - Directs cooling water through the engine to maintain proper operating temperature.. • OEM Fit Precision - Built to Yamaha specifications for correct alignment and secure installation.. • Corrosion-Resistant Build - Designed to handle long-term exposure to water and marine conditions.. • Supports Engine Protection - Helps prevent overheating and protects internal components.. Compatibility. Compatible with select Yamaha outboard engines using this water tube