Originally Posted by AlanBrown
Recently experienced a problem with my 1981 Hunter's Yanmar 2GM. Here's what happened.
Started engine and only got 1/2 the normal flow of water out the exhaust. Checked raw water inlet and strainer. All clear.
Noticed stream of warm water flowing out of engine compartment into bilge, but engine ran fine.
Water stopped coming out with exhaust. No exhaust either. Engine compartment got quite warm.
I suspect that the heat exchanger finally bit the dust. Your thoughts and suggestions.
Boat is back in the Bahamas, so I can't do any personal troubleshooting from here.
If the engine's not overheating, it's probably not the heat exchanger.
Sounds to me like the hose between the heat exchanger and the mixing elbow came loose. I'd check that first. Second thing I'd check is carbon buildup in the mixing elbow itself. Third thing I'd check is to see if your muffler's leaking.
Check the easy stuff first.
Hate to sound snarky, but have whoever's got your boat crank it and look in the compartment to see where the water's gushing out of. Chances are that's the source of the water.