Yamaha - Tube, water 1 - 6CJ-44361-10-00Yamaha Water Tube 1 Cooling System Tube 6CJ 44361 10 00 Overview On a Yamaha outboard, cooling flow is everything, and this water tube is a key part of that system. Its what carries water from the lower unit up into the powerhead, and if its not right, the engine will let you know fast. Ive seen overheating issues come down to something as simple as a misaligned or worn tube. When its set up properly, water flows steady and the motor stays cool even