water in the oil

[81merc]

Hello members,

I started to get the boat out for the spring and think I have a problem. while the boat starts and actually runs fairly well, there are a couple issues. the first is that there is a ton of white smoke (I thiink its actually steam) coming out of the exhust and also I clearly have water in the oil.

Now I know the steam / smoke issue has to be a cracked intake/exhaust manifold. What I'm not sure of is if this is the right cause of the water in the oil.

I removed each plug and tested the compresion of each cylider and each one tested out with good compresion, none of the plugs looked wet either. So I'm strugelling in my head about how a cracked manifold is letting water into the oil. If its taking water into the intake vales would that not make it run very poorly if at all?

I've priced out the manifold and its about 300 new. I just don't want to bolt on another 300.00 just to find its got a bad block and was a waste of money.

The motor is a 1981 mercrusier 120 horse 4cyl (the iron duke).

Any help or advice on other things to check would be greatkly appreciaited.

Thanks,
Doug

 

[dubs283]

Re: water in the oil

120 mercruiser is not the iron duke - that was only used in cars, never in boats

have you considered a cracked block??

was the engine properly winterized??

 

[Fordiesel69]

Re: water in the oil

Where are you located city / state?

The 120/140/165 is noted for cracked or rotted out manifold for two reasons. People do not winterize the manifold becuase they do not know how to, or simply assume it drains with the engine block. Secondly the casting simply rots away and now you have pin holes.

YOu can pull the manifold off, fill the water jacket with water or gasoline, and watch it leak into the exhaust or intake. This will rule it out for sure.

These engines also crack externally up top where the block and head meet, rarely you will never see these crack internally like the V8's.

Lastly the headgasket can go south, but it is not as common as you read about here. Its mostly when it has been overheated.

 

[81merc]

Re: water in the oil

Really not the iron duke? I assumed that it?s the same block as used in the car... interesting trivia. So does that mean the block is made direct by Merc or is it still a different generation Chevy block?

Winterization is for sure where the issue started. Now it?s just trying to determine how bad it is. I'm in southern Michigan (West of Ann Arbor).

You both bring up exactly what?s on my mind - head gasket, cracked block or something else in the engine. If I knew, or even thought it might be only the manifold damaged (which is cracked for sure, no question there, its shot) I would invest the money and put a new one on. I just hate to spend that 300 just to find out that I have another issue someplace in the engine and still get water into the oil. which is what I'm wondering how to check to detirmine if there is an issue.

Taking the manifold off and filling its water jacket to see if it leaks into any of the intake side might be a good way to make an educated guess if that?s where the water is coming from. But what I can't get out of my thoughts is if there is water getting injected into the fuel / air mixture would the engine still even run? Wouldn't it either barley run or maybe show signs on the spark plugs or a combustion problem?

 

[Bondo]

Re: water in the oil

Really not the iron duke? I assumed that it?s the same block as used in the car... interesting trivia. So does that mean the block is made direct by Merc or is it still a different generation Chevy block?

Ayuh,... The Iron Duke is a Pontiac based 151cid...
The 2.5l in boats are Chevy based 153cid motors...
Two very different motors...

I'd guess the block is cracked as a cracked manifold can't put water into the oil...
Not without seepin' past the rings...

 

[mkast]

Re: water in the oil

Now I know the steam / smoke issue has to be a cracked intake/exhaust manifold.

I just don't want to bolt on another 300.00 just to find its got a bad block and was a waste of money.

You are sure the problem is with one of the manifolds. How did you decide this?
Have you looked at the dip stick?

 

[81merc]

Re: water in the oil

I'd guess the block is cracked as a cracked manifold can't put water into the oil...
Not without seepin' past the rings...

yup thats exactly my thought as well. its why I hesitate.

You are sure the problem is with one of the manifolds. How did you decide this?
Have you looked at the dip stick?

thats a good question... I know there is aleast an external crack becuase it's dripping a little water from the bottom and it feels like its cracked right there. That along with the pluem of white smoke or steam coming from all of the exhaust outlets seems alot like what it would do if there was water getting mixed with the exhaust. but I guess thats not to say it has to be cracked, if there is other causes of the white smoke or steam I'm all ears to check those before pulling out the wallet and buying un-needed parts.

doing some internet searching I found the attached pic:


Makes me think I can pull the carb and the the carb mounting plate off and see if there is any visable intake cracks.

 

[81merc]

Re: water in the oil

oh yes - did look at dipstick. oil level is quite a bit above full, and it is very milky

 

[mkast]

Re: water in the oil

oil level is quite a bit above full, and it is very milky

Time for a new block/engine.

 

[81merc]

Re: water in the oil

saw this interesting thread - http://forums.iboats.com/showthread.php?t=439122&page=1

Seems like it some of the same story I'm seeing as far as the oil goes.

I did pull that carb and its mounting plate off. While I wasn't able to see any visable cracks it sure had a bit of scaling and rusting in there. so no doubt there was some water getting in that way. But also as Bond-o says water from manifold needs to go through the rings. The compresion on each cyl. holds about 75psi so its not blowing enough by to put that much in the water. leaving a crack some place in the engine itself.

Bottom line looks like is replace engine or donate the boat as-is (its an old thompson and I'm not sure its worth putting much into.)

Any tips on tracking down a short block 3.0? Is there a good online source?

 

[Bondo]

Re: water in the oil

saw this interesting thread - http://forums.iboats.com/showthread.php?t=439122&page=1

Seems like it some of the same story I'm seeing as far as the oil goes.

I did pull that carb and its mounting plate off. While I wasn't able to see any visable cracks it sure had a bit of scaling and rusting in there. so no doubt there was some water getting in that way. But also as Bond-o says water from manifold needs to go through the rings. The compresion on each cyl. holds about 75psi so its not blowing enough by to put that much in the water. leaving a crack some place in the engine itself.

Bottom line looks like is replace engine or donate the boat as-is (its an old thompson and I'm not sure its worth putting much into.)

Any tips on tracking down a short block 3.0? Is there a good online source?

Ayuh,... craigslist,....

There's Tons of rotten boats, with 3.0l motors in 'em...
Buy the Rotten boat, bone it out for parts, use what ya need, 'n sell the rest...
You might actually come out Ahead...

 

[starsnstripers]

Re: water in the oil

I thought the Iron Duke was the 155ci v-6 Buick motor?

 

[cr2k]

Re: water in the oil

The inline GM based 4 cylinder motors are Marinized industrial engines like on a cotton picker or a forklift.

Wondering how you "ruled out" anything other then manifolds? Usually any manifold leaks will cause wet/rusty plugs. Where as a cracked block does not have any contact with the intake/exhaust system.

 

[81merc]

Re: water in the oil

Wondering how you "ruled out" anything other then manifolds? Usually any manifold leaks will cause wet/rusty plugs. Where as a cracked block does not have any contact with the intake/exhaust system.

I wouldn't say the manifold was ruled out, actually I think the manifold has a problem for sure. The extent of the problem is what I'd say I'm un-sure of. As well as if there is a block / head problem in addition to the known manifold issue.

As far as the plugs go they all looked about the same normal, maybe a little sooty, but none of them looked wet or rusty.

That said, I only even call the manifold problem as "known" becuase it seems like the only way so much water can make it into the exhaust to create as much steam as it does.

The other main un-known for me is can water in intake equal alot of water in oil without making the engine run bad. As it seems to me if there comes alot of water in with the gas/air mixture it would be sure to effect the engine running (if it will run at all).

The signs I could see made me think that the bad winterization this year finished off the manifold and my gut told me "don't put 300.00 into it becuase the water in oil might mean a block issue". I was secretly hoping someone would tell me of a way that water from the manifold (either intake or exhuast) could get into the oil pan so the engine (which runs ok for the little it was run this year) should be fine with just a new manifold. Since I'm not hearing of such a gateway for water besides the rings (again seems like this would effect the way it runs).... I think cracked block to match the crack manifold makes most sense and this beast is hurt.

On a good note I did do a bunch of Craigslist searching and within a couple hour drive there is a few of these run down boats (most even come with a trailer) that Bond-o talked about. The ones that look soild and state "can hear run" seem to hang in the 1,000.00 range, the ones that are ragged out run in the $400.00 range but most of these state "started a couple years ago" or "ran good when it was parked here". The later of those make me a bit worried I'll end up with a second boat with a bad motor. I guess if I really want to answer the original question I could by one of these with a good 120 and verify the "new one" runs well with no water leaks, then pull the manifold and put it on my current motor and run it with fresh oil. and at the end of the day if by some long shot the water doesn't show back up in the oil then I could re-sell the "new" good engine. It would be a bit more work, but would leave no doubt.

Another question, if I'm putting in a used motore will a v-6 or v-8 merc motor of the same generation bolt on and work with the outdrive side of things that I have with the inline 4 now? I saw a couple v-8's out there an couldn't help but think "that seems faster" . Plus upgrading makes it more like an "oppurtunity" then a screw-up on the winterization.

Thanks,
Doug

 

[Bondo]

Re: water in the oil

Another question, if I'm putting in a used motore will a v-6 or v-8 merc motor of the same generation bolt on and work with the outdrive side of things that I have with the inline 4 now?

Ayuh,... The only way that'll work is buyin' a runnin' donor, 'n swappin' EVERYTHING painted black...
Pulleys to Prop....