GM3.0 omc crack in exhaust manifold

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dtdan

Cadet
Joined
Aug 25, 2005
Messages
6
Have a weekend planned and going though boat and found a crack in exhaust manifold on the bottom. It also holds the carb on so also a intake. If I grind it good can I get away with a JB Weld for the weekend and if so will I just watch for overheating? Do I leave it home and order part?:'(
 
Bondo

Bondo

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Apr 17, 2002
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70,513
Re: GM3.0 omc crack in exhaust manifold

Roll the Dice,.............

Just how Lucky are ya Feelin'....??.....
 
O

oh-u812?

Petty Officer 3rd Class
Joined
May 29, 2006
Messages
76
Re: GM3.0 omc crack in exhaust manifold

I have the same set up and it leaks too. I've been running mine all summer. I just check my oil, temp and bilge very frequently.
 
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DangerDan

Petty Officer 1st Class
Joined
May 21, 2005
Messages
260
Re: GM3.0 omc crack in exhaust manifold

JB Weld will fix it real good,,, right up to the time the maniflod heats up and the patch crystalizes & cracks again. Been there done that.

You could possibly have it braized for a temporary fix until your ready to change the manifold. Thats about the best repair you'll get that will hold until you do it right.
 
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dtdan

Cadet
Joined
Aug 25, 2005
Messages
6
Re: GM3.0 omc crack in exhaust manifold

I know the right thing to do is change but last August I couldn't use because outdrive seals. Got that fixed in spring and used it 1 time this summer and 5 days before I finally have time to go I find this. Sorry just :'(
 
C

cobra 3.0

Lieutenant Commander
Joined
Jul 31, 2003
Messages
1,797
Re: GM3.0 omc crack in exhaust manifold

I have done it on mine two seasons ago and it still is fine. My crack was in the belly and in length. I grinded it completely out with a dremel and thin wheel all the way through making sure it was grinded to the raw metal right through the crack. I then applied the JB. If it is done right, it will last a very long time in FRESH water use.

If it does end up leaking again, it's not like you'll be stuck somewhere. It'll only drop water in the bilge that the pump can get rid of.
 
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