OMC Cobra 4.3l Upper gearcase crack

R

rick bynum

Recruit
Joined
May 14, 2013
Messages
2
My OMC motor has developed a crack in the upper gearcase assmebly housing right below the bolts. It is a 4.3l V6 on a 1994 LOWE deck boat. Will JB weld suffice to fill the crack or do I need to get it welded? Can it be welded? Is it alumnimum or steel? Just need some advice on where to start. We bought the boat in 2006 and photos show the crack was not present then. We assume the crack has been there for a couple of years but enlarged this winter. We just never noticed it before but it looks like it is actually been "repaired" and covered up..not sure. The boat has always run fine but there was no crack when we bought it in 2007. My other question is why is, what looks like a 1992 4.3L on a 1994 boat? crack small.jpg crack zoom.jpg
 
sam60

sam60

Captain
Joined
May 21, 2011
Messages
3,189
Re: OMC Cobra 4.3l Upper gearcase crack

Advice on where to start would be to post some pics. That would help to describe the location of the crack. Also if you put all of the boat info in your signature, you won't have to explain what your boat and engine/drive is again. Also look for a OMC issued service manual specific to your setup.

I'm not an old timer here or any sort of expert on anything, just offering advice that I've learned here, welcome to iboats, Rick!
 
D

Dawna12

Recruit
Joined
May 26, 2013
Messages
1
Re: OMC Cobra 4.3l Upper gearcase crack

rick bynum said:
My OMC motor has developed a crack in the upper gearcase assmebly housing right below the bolts. It is a 4.3l V6 on a 1994 LOWE deck boat. Will JB weld suffice to fill the crack or do I need to get it welded? Can it be welded? Is it alumnimum or steel? Just need some advice on where to start. We bought the boat in 2006 and photos show the crack was not present then. We assume the crack has been there for a couple of years but enlarged this winter. We just never noticed it before but it looks like it is actually been "repaired" and covered up..not sure. The boat has always run fine but there was no crack when we bought it in 2007. My other question is why is, what looks like a 1992 4.3L on a 1994 boat? View attachment 193934 View attachment 193935
Click to expand...

Hello, I was just about to post on here looking for a 1990 OMC Cobra upper casing. I have a crack in mine identical to yours. The boat has been well cared for and this crack came as a huge shock to us. Anyone out there know where I could find one? I don't need the gears, only the casing. My pics are identical to these.upper case2.jpgupper case.jpgupper case2.jpgupper case.jpg
 
Bondo

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,524
Re: OMC Cobra 4.3l Upper gearcase crack

Ayuh,.... You guys didn't properly winterize yer boats, 'n left the drives Up...

That's Freeze damage from trapped water....

When's the last time either of those drives have been pulled, 'n serviced,..??
 
Idlespeedonly

Idlespeedonly

Senior Chief Petty Officer
Joined
Jun 30, 2011
Messages
779
Re: OMC Cobra 4.3l Upper gearcase crack

Yep. That is the cavity were the shift bellcrank is located.
 
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