Re: 1988 OMC Cobra 7.5L Engine DEAD?
Funny thing , the oil does not look at all milky on the dipstick, however it is 2" above the full mark. I could be that the water leaked into the oil pan after the motor was shut off, as I only had it running about 2-3 minutes when the overheating occurred
Howdy,
I had a similar problem with the 460 King Kobra I had in my 87 Four Winns 211 Liberator.
I don't think I had a lot of water in the pan but there was some. I had leaky riser gaskets on both sides. It allowed water to run back into the cyls that had open exhaust valves when I shut down.
Then it would hydrolock if I tried to start it immediately after shutdown and for about 30 min thereafter.........If I let it sit longer, it would usually crank right up (presumably after the water leaked past the rings)
It did this for quite some time.......until I removed the engine the following winter.
If you have a few inches of water in the pan I would think it's more than just leaky riser gaskets. You just cannot get all that much water past the rings.....and if you get it started, and run it for a while, the little bit of water evaporates out rather quickly.
It's possible that you might have a severely corroded intake manifold, enough that it's allowing water into the "valley", a cracked block or a cracked head.
You will have to make your own decision........
When I pulled my engine, I was unable to find replacement exhaust manifolds.....then they became available for some ridiculous price of $1600 EACH!!
The coupler was NOT available and there were several parts for the drive that were NLA (or ridiculously priced used etc)
This was only about 5 or 6 years ago...... I understand that Sierra NOW has couplers again and there's someone actually making exhaust manifolds for the 460 again. (albeit DOUBLE the price of other manifolds!!) There are companies that will rebuild the drive too....
http://www.allamericandriveservice.com/OMCCobra.html
So you're not DEAD in the water as it were.........
I decided to DUMP everything though and I found a used 454/Bravo III setup locally from a wind damaged boat and bought the whole shoot'n match for $5k and replaced everything.
I subsequently sold all the OMC Junk, piece by piece over 3 years or so for a total of about $3500.
Now, if you wanted to replace the engine you could easily find a truck engine that would probably work just fine..........just MAKE DOUBLE sure that your exhaust manifolds and risers and coupler are serviceable (Those are MAJOR show-stopper parts)
Part it out, anyone who does relies on a mechanic shouldn't even consider owning a Cobra, not bashing mechanics just saying your kinda over a barrel with that one. Don't take it wrong but unless you are your own mechanic the obsoleted cobra Drive will destroy your finances.
Yeah.......it's hard to argue with that attitude...... I went through a LOT of gyrations on how to fab a different coupler when I couldn't find one, and go with different manifolds etc.....
There are still a LOT of 460 King powered boats out there. The used parts supply is slowly drying up. People are willing to buy all the parts. (I sold my old KC drive for $1450 to a guy on the east coast and he paid the shipping !!)
I sold my flywheel housing to a guy in CA that was going to have to part out his boat after he hit something submerged and his coupler literally EXPLODED. He couldn't find a flywheel housing anywhere!!! His insurance company was going to "Total" his boat because it wasn't worth repowering. (80's 26ft Bayliner)
I sold my Exhaust Y-pipe to a guy in FL when his severely corroded y-pipe started leaking and nearly sunk his boat!!! You cannot buy them either!
Anyway, you get the picture.
A Mercruiser BBC/Bravo will bolt right in. the transom cutout is the same (you do have to drill 2 additional holes for the 8-stud Merc transom-mount though)
Good luck! I was there about 5 years ago!
Rick
