Overheated Engine - Water in Oil

51Magnum

Cadet
Joined
Jul 15, 2010
Messages
6
I got a SB 350 (5.7L) OMC engine. We overheated it the other day, and yes it was HOT. I took it out for the first time after overheating it, melted the exhaust bellows, on the lake the other day and when I went to start it, it just clicked. Did not turn at all. I worked at it for a few minutes and finally got it to spin over (lettting the starter cool in between cranking). I thought at first that I might have spun a bearing.

I took the valve covers off today and found the good ol chocolate milk on the top end. I then took the spark plugs out and turned the engine over by hand and pumped a bunch of water out of one of the cylinders. Does this sound like a head gasket? I don't see any milk on the dip stick, but it could have settled over the last week.

should I just start tearing it down from the top? Or should I take the motor out and look at the bottom end.

I think it must be a top end problem and not a spun bearing.
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Re: Overheated Engine - Water in Oil

Look at the risers and gaskets, it if got real hot then that area could have warped and now the gasket leaks, and then water can run into the exhaust passages then on into any cylinder with an open valve.
 

Lakes84

Petty Officer 1st Class
Joined
Aug 28, 2011
Messages
253
Re: Overheated Engine - Water in Oil

Almost my issue to a Tee. Here's my thread and what the experts told me
 

51Magnum

Cadet
Joined
Jul 15, 2010
Messages
6
Re: Overheated Engine - Water in Oil

Thanks for the help. I took the risers off and this is what I found:

Boat; Engine 001.JPG

Boat; Engine 002.JPG

Boat; Engine 003.JPG


I think this is my problem. So thinking about what happened, I thought the engine was stuck, i.e. a bearing freezed. But now I think it was liquid locked, water in a cylinder.

So is there any way to use the rubber boot or should I get a new one?

Boat; Engine 004.JPG

Thanks again for all your help.
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Re: Overheated Engine - Water in Oil

So is there any way to use the rubber boot or should I get a new one?


If you are kidding then LOL! yes get a new one.

If you are not kidding then, yes get a new one because the exiting raw water from the cooling system will leak out into the boat at an alarming rate.

Don't you have two of the boots? I would do them both as everything rubber would be suspect now. I am not sure about your model of drive, but there could be flappers (or by now could have been) inside the exhaust pipes, and those could have melted and been blown on out and stuck in the drive exhaust passages somewhere.
 

51Magnum

Cadet
Joined
Jul 15, 2010
Messages
6
Re: Overheated Engine - Water in Oil

If you are kidding then LOL! yes get a new one.

Yes, of course I was joking....... I guess I should have added a smiley face. I have two on order and should be back in business in a few days.

I didn't see the flappers but I will check to make sure they are not down in the exhaust somewhere. Thanks for the suggestion.
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Re: Overheated Engine - Water in Oil

Good deal. I think I should have typed "Duct tape is your friend" as I was almost certain you were kidding :D

Posts like this are seen by many searchers after the fact and I wanted to be sure all would understand the jesting, and also why it is important if they did not get the joke.

Good luck!
 
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