Is there any hope? ...

[CarterCustoms]

I have an '86 Mercruiser 140 that recently overheated, about 200 deg. By the time I got her back to shore I noticed oil/water mix coming out of the flame arrestor vent tube. Upon further inspection when I got home my oil pan was full of water, so much so that it had vented out of the valve cover. Immediately I knew this had bad news written all over it. I decided to do a compression test to start. When I turned the engine over water sprayed out from the head gasket onto me! There was also water in the bilge so I think the manifold gasket is blown as well. My question is can I salvage this engine and if so can I do it without doing a complete rebuild? I have limited knowlege of marine mechanincs so any help would be greatly appreciated.

 

[CheapboatKev]

Re: Is there any hope? ...

Have ya gotten all of the water outta the engine?
Pulled the plugs and turn her over till no water shoots out?
Dont let her sit with water in the cylinders

 

[Don S]

Re: Is there any hope? ...

My guess is, since you just bought this boat, you never did a test drive, and this was the first time taking it out.
You probably have a cracked block, caused by failure to winterize or winterize correctly.
You asked in your first post about this boat if you got burned. Between the bellows and all, now this, I think you did.

 

[CarterCustoms]

Re: Is there any hope? ...

I drained the oil pan and cranked it over a few times, I was afaid to do it too many times I didn't want her to sieze up

 

[CarterCustoms]

Re: Is there any hope? ...

My guess is, since you just bought this boat, you never did a test drive, and this was the first time taking it out.
You probably have a cracked block, caused by failure to winterize or winterize correctly.
You asked in your first post about this boat if you got burned. Between the bellows and all, now this, I think you did.

How dumb do you think I am? I know I'm a newb at the marine stuff but give me a break. Actually I did test drive it. Was on the water a couple of hours with no problems with the previous owner. No water in bilge or anything. I looked this thing over good. I had the bellows replaced because they were showing signs of wear and were about to tear. The engine stuff is an all new problem, just bad luck I guess. Don't get me wrong I appreciate the advice but don't assume I am an idiot just yet lol. If there is no crack, is it salvagable?

 

[meesh]

Re: Is there any hope? ...

Pressure test the cooling system and that will tell you real quick if it's fixable or time to replace.

 

[CarterCustoms]

Re: Is there any hope? ...

Pressure test the cooling system and that will tell you real quick if it's fixable or time to replace.

At the risk of sounding dumb (again apparently), how do you do that?

 

[cooter2506]

Re: Is there any hope? ...

With that much water I think it is useless to to a pressure test it is a cracked block.

 

[totx]

Re: Is there any hope? ...

There was also water in the bilge so I think the manifold gasket is blown as well.

Why?

Manifold gasket is not causing any water leak....

 

[grahamh]

Re: Is there any hope? ...

Pressure test the cooling system and that will tell you real quick if it's fixable or time to replace.

If water is spraying out, you already know there's a problem, no need to pressure test the cooling system, but you do need to pressure test the HEAD once it's off.

I would pull the head off, and then have it pressure tested by a machine shop. It will probably need to be resurfaced as well. May as well replace the manifold gaskets as well as long as the head is off. Also make sure none of the valve seats have been dropped.

Personally, I would bet against the block being cracked. From what I've seen (in cars, at least) overheating causes blown head gaskets and warped/cracked heads, but I've never seen a block crack from overheating. The machine shop will tell you if your head is repairable.

I don't know how comfortable you are working with engines, depending on your comfort level, it may be time to take it to a mechanic.

Also, to answer your original question, my guess would be that the bottom end of the motor is fine.

 

[Don S]

Re: Is there any hope? ...

Personally, I would bet against the block being cracked. From what I've seen (in cars, at least) overheating causes blown head gaskets and warped/cracked heads, but I've never seen a block crack from overheating. The machine shop will tell you if your head is repairable.

Blocks crack from poor winterization. Manifolds crack, blocks crack, most of the time they leak externally too. (water in the bilge).
The blocks can crack internally also which dumps water directly into the oil pan. Here on the forums, it's a common occurance in April and May. Lots and lots of "Milky Oil" threads.. EVERY YEAR, not just this one.
There is also lots of posts with people buying old boats only to run them and find milky oil bubbling out everywhere. This is not a new problem to this forum.
Of course if the crack is small, it may take a while to fill the oil pan till it bubbles out, but it's still cracked.
To the original poster. After you did the test run for a couple of hours. Did you check the oil and see if it was still clean and clear and on the full mark?
I would be looking for external cracks on the manifold and the block under the manifold. You may not find a crack, but keep an eye open for JB Weld repairs on both. It's a lot more common than you think.

 

[grahamh]

Re: Is there any hope? ...

Blocks crack from poor winterization. Manifolds crack, blocks crack, most of the time they leak externally too. (water in the bilge).

Exactly. I was assuming that there were no problems with water in the oil prior to the overheating incident.

 

[Don S]

Re: Is there any hope? ...

200? will not crack anything. Todays cars run highter than that normally. A marine engine needs to be kept cooler because it's enclosed in a small compartment plus higher temps are bad in salt and brackish water.

 

[CarterCustoms]

Re: Is there any hope? ...

To the original poster. After you did the test run for a couple of hours. Did you check the oil and see if it was still clean and clear and on the full mark?

I will admit I did not do this, never even crossed my mind that would need to be done AFTER running. Ignorance on my part I guess. I checked the oil level before going out and it looked normal, but anything can happen after running awhile I guess. I have accepted the fact that I probably got burned but nevertheless I still have to tackle this issue.

Should I try to tear her down and do a rebuild only to find that the block is junk or should I try to get a reman engine and repower her? What is more cost effective?

 

[IVAZ]

Re: Is there any hope? ...

You need to figure out if the block is cracked. Have you looked for cracks or jb weld the way Don suggested? If you saw water coming from the area where the head meets the engine, remove the head to check the gasket.

If the block is cracked I wouldnt repair it. I would find a different block and rebuild it.