How many transom bolts,omc cobra?

bfd72

Cadet
Joined
Jul 31, 2005
Messages
9
i would like to know, on my 1988 omc cobra, how many bolts are involved in bolting the transom mount where it bolts through to the inside plate/mount,( for lack of a better word on my part) inside the stern of the boat? i have discoverd a significant leak at this part of my boat yesterday while out on the lake (pulled boat out and while on incline of the ramp got out and ovserved the water that had leaked in was now gushing out between the stern of the hull & thetransom mount) and when i got it back home i found some loose bolts at this spot on the inside of the boat, where the transom mount and the stern attach together , i am only able to see 4 bolts that are holding this all together, looked around with a mirror and light, aruond the exhaust-y, but its pretty limited access below there, does anyone know exactly how many bolts are holding this on, the first 4 were fairly loose as stated earlier and i would like to make sure i get all of them tightened, if there are more involved than the obvious 4 , also is there a gasket that fits between the stern and transom mount ? i don,t find one shown anywhere, listed on the exploded parts schematic, online where i normally buy parts for this outdrive, someone told me there is,nt a gasket its just a dry fit (seems odd to me if there would,nt be one!!) i also met a guy on the boat ramp yesterday, who said he has same outdrive and also had a bad leak before and his mechanic told him to tighten bolts & run a bead of marine grade caulk around outside of the transom mount, is this an accepptible fix ? if so what is the best type/brand of caulk to use if done that way? thanks bfd72!!!!
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: How many transom bolts,omc cobra?

There are 6 studs with nyloc nuts on them. They don't come loose. What happens is the transom is probably rotton and the wood is going away, or something other than the transom shield itself is leaking.<br />If you found 4 bolts loose, then the transom needs repair. Tightening the bolts and caulking the outside might get you through the season as a bandaid type patch, but it's not how to fix it. That transom is also the support for your drive and engine, and with it flexing due to the rot, you will continue to have problems, including alignment problems and may loose a coupler.<br />The engine, drive, and transom shield needs to come out and the old rotted wood needs to be removed and new wood put in it's place.
 

sea wolf

Lieutenant Junior Grade
Joined
Apr 3, 2002
Messages
1,219
Re: How many transom bolts,omc cobra?

A few years back I also had a bad leak from the transom. The boat would fill up with water in no time. Had to pull the engine to find out what was going on. It turned out to be a bad seal between the engine & transom mount. Replaced the seal & problem solved. Don't ask me exactly where the seal is located, I don't remember. OMC Cobra, 3.0.
 

sea wolf

Lieutenant Junior Grade
Joined
Apr 3, 2002
Messages
1,219
Re: How many transom bolts,omc cobra?

A few years back I also had a bad leak from the transom. The boat would fill up with water in no time. Had to pull the engine to find out what was going on. It turned out to be a bad seal between the engine & transom mount. Replaced the seal & problem solved. Don't ask me exactly where the seal is located, I don't remember. OMC Cobra, 3.0.
 
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