I have a 1981 Bayliner Santiago with a 165 Mercruiser straight 6 motor. It has a closed cooling system. It is overheating all the time now. Boils the water right out of it. I have replaced the outdrive water pump and then the entire outdrive and it still overheats. I can find no leaks of any kind anywhere. Someone told me that they thought that the hose routing was wrong. I had it out yesterday and it overheated in 2-3 minutes at an idle. I felt the heat exchanger and it was cool but there was only steam when I loosened the cap on the closed system. The person that said the hose routing was wrong said that the hose going back from the heat exchanger should run through the exhaust manifold from front to rear. Mine returns directly to the riser at the back of the manifold. I also saw alot of lake water bubbling and churning right where the outdrive attaches to the transom. I hadn't noticed this before. I thought all exhaust from the motor ran out through the propeller location. I obviously don't know much about boats. Any help would be greatly appreciated. Thanks in advance. Ron.
