I was running my engine at the dock yesterday, and a neighbor pointed out that water was exiting in two different places: the exhaust port, and what turned out to be the port side cockpit drain. I had never noticed this before. I soon discovered that the hose that runs from the seawater outlet on the heat exchanger to the mixing elbow has a T in it, with a hose that runs back through the cockpit locker to the top of the port side cockpit drain.
From what I can tell, Yanmar's design has the hose going straight from the heat exchanger to the exhaust elbow. I had always assumed that hose was a siphon break or something, but it doesn't make much sense if it's filled with engine water. Does anyone else have this on their engine?