water on top of cylinders

[Jeffropicaso]

Hello, This is my first time posting on here. I have a 5.7 L PCM engine in my boat. I took it out and ran it after doing some maintenance on it....change fuel filters, fuel pump, oil, etc. The engine cranked and ran fine for about 2 1/2 hours. Oil psi was good and the water temp was good. I went back to the dock to pick up some friends and left the boat running at idle. It sat idleing about 15 minutes and all of a sudden it seemed somebody just walked up and turned the key off. The engine died and when I attempted to re-start it it acted like it had locked up. I pulled the spark plug on the rear left bank cylinder and water came out of the hole. I then pulled the rest of the plugs on that side and water came out of the next 2 cylinders. I then seperated the exhuast manifold from the head to see if it was coming from the head side or the manifold side. there was no sign of it coming from either side. By the way it is a fresh water cooled engine as well. The water was clear not mixed antifreeze. Does anybody have any clue to where i might have the water entry from. I'm going to try and pressurize the fresh water side and see if anything becomes present. I don't beleive it is from the head gasket, because it never ran hot sense i have ran the boat. I have the Alpha 1 out drive in case anyone needs to know. Any information would be greatly appreciated.

 

[Don S]

Re: water on top of cylinders

Sticking or bad exhaust valves can cause water to be sucked back into the engine. Especially after long periods of idle. Might want to give it a compression test to find out.
Could also be a leaking gasket between the riser and manifold. But that usually shows up after you shut the engine off, not while it's running.

 

[Jeffropicaso]

Re: water on top of cylinders

ok, I pressurized the fresh water side of the engine to about 10 to 15 psi....no water coming from manifold or head. I was told that the exhaust bellows does not have to be attached to the outdrive. Currently it is not. I'm wondering if the waves from other boats could push water into the exhaust and cause the problem that accured. The only raw water introduced is thru the aftercooler on the engine. According to the water flow chart in my manuel. Don, I don't understand your theory of bad exhaust valves having anything to do with water being introduced into the cylinders....it just don't make sense to me. Especially when the engine doesn't smoke, spit or sputter when running. There should be some sign of wear while the engine is running. I would say i'm mechanically inclined beings I have pulled wrenches for over 22 years, just not on i/o engines it seems pretty simple looking at logic. I thought I would pick some brains that has had experience with the inboard outboard vessels. I think I will purchase the bellows for the exhaust and install it. That right there will give me a good sense of what happened. Granted it doesn't happen again after I install it. Thanks for the views and would have hoped there would have been more ideas posted other than the 1 I got. Thanks anyway