Surprise Surprise!

beericks

Seaman Apprentice
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Jul 30, 2009
Messages
46
I took off my exhaust manifold to replace what I thought was a leaky gasket and I saw this. Just to be for certain this is not normal right? 1973 Mercruiser 140IMG_0489.JPGIMG_0492.JPGIMG_0493.JPG
 

Don S

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Re: Surprise Surprise!

To me, it looks like a typical non winterized 3.0L that froze and cracked. You might be able to patch it, but the problem will be if it's cracked INSIDE the engine and fills the oil pan full of water.
Look at all the water in the oil threads in this forum.
 

lcmains1

Petty Officer 2nd Class
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Apr 22, 2011
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Re: Surprise Surprise!

Looks like a crack to me.... I foght that with an old boat and lost the fight... Sorry man... not good
 

beericks

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Re: Surprise Surprise!

Well here is the positive part. No water in the oil and from the rust that you can see it has been doing it a long time. It is just leaking water so I mixed up some JB Weld and put it on it. I guess if that doesn't work I can always braze it. But i guess turning on the sump pump every hour isnt so bad either. It just frustrates me :D
 

Don S

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Re: Surprise Surprise!

Well here is the positive part. No water in the oil

You also haven't run it. Until you run it, you aren't going to get water in the oil.
 

Howard Sterndrive

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Re: Surprise Surprise!

I had a 3.0 with a crack there - JB welded it - lasted a few seasons. I had another 3.0 I bought used that had been arc welded same place.
Occasionally the 3.0 seems to be more forgiving than other motors about how they crack.
 

Bondo

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Re: Surprise Surprise!

Ayuh,... So long as it ain't leakin' into the oil,...
I've seen 'em glued, 'n run, for Years...
 

Fireman431

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Sep 17, 2007
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4,292
Re: Surprise Surprise!

Hopefully, no water intrusion. in the meantime, start checking CL or repair shops for deals on manifolds/risers. It won't last forever.
 

beericks

Seaman Apprentice
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Jul 30, 2009
Messages
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Re: Surprise Surprise!

I guess I wasn't clear about my post this crack is on the actual block not the exhaust manifold. I couldnt see the crack until I pulled off the exhaust manifold. I have been running this boat for 3 years now without doing anything to the crack and do not have any water in the oil. It only leaks water from that spot. So I think that I got lucky and the water jacket is the only thing that cracked. What gets me is the freeze plug right below it should have blown out not the cast iron block ugh!! Oh wells I guess this is my first boat and you have to start somewhere
 

Bondo

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Re: Surprise Surprise!

What gets me is the freeze plug right below it should have blown out not the cast iron block ugh!!

Ayuh,... Maybe because it's a Core plug, from the sand casting used to create the part...

They only work as freeze protection when it freezes, 'n thaws...
If it freezes solid 1st shot they usually don't...

Clean it up, 'n epoxy over, then go Boatin'...
 

sschefer

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Nov 13, 2008
Messages
4,530
Re: Surprise Surprise!

Ayuh,... Maybe because it's a Core plug, from the sand casting used to create the part...

They only work as freeze protection when it freezes, 'n thaws...
If it freezes solid 1st shot they usually don't...

Clean it up, 'n epoxy over, then go Boatin'...

Finally somebody that knows what their called and what they're for... Very refreshing!


JB weld should get you going but do keep an eye on the oil. Clean it really well, hit it with a MAP gas torch just long enough to pull the oils to the surface and burn them off then wash it down with Acetone and apply the JB.
 

beericks

Seaman Apprentice
Joined
Jul 30, 2009
Messages
46
Re: Surprise Surprise!

Ok sounds good thanks for the info guys!! I will be going fishing tommorow woohoo!!
 
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