OMC Cobra.

[rolmops]

I just bought a 1989 22 foot Starcraft Islander with trailer for $1500. The boat hull and trailer are in good condition, although I will have to replace the deck and possibly the transom although the rot there only seems to be in a small spot near the port end of the stern. It does however have a 4.3 liter OMC Cobra and I have no experience with those engines at all. Are they trustworthy or should I just tear it out and install a 4.3 liter mercruiser instead or even better, add a rear section and install an outboard. I'm not sure those hulls can handle that extra weight during transport.

I would appreciate any advice, thank you.

[Shakemsam]

No personal experience with OMC I/O's. But I believe the general consensus was stay away if you can. Parts are pricier and harder to find than merc. The Cobra's were a better outdrive than previous versions but still not merc. An outboard bracket would be an interesting project. Since you are rebuilding the transom anyway, that's the direction I would go.

[MCF]

When Outboard Marine Corp when bankrupt arround 2000 or 2001 they got out of the outdrive business and sold the Cobra business to Volvo, so the problem becomes time, the availability of parts and the availability of someone who can repair them.  If you could I would move to the consideration of doing a Mercruiser change out if possible.  The outboard bracket project would be interesting just becomes an unknown in terms of a template to accomplish it. 

[bulletbob]

  Does  the 4.3  start and  run well?... Is the outdrive functional and in decent shape?.... If so, why  do anything at all?... the OMC engine  is a plain old 4.3 GM motor at heart,  slightly  modified for mari;ne use of course, but parts are readily available and not expensive .. A rebuilt OMC 4.3  engine with a 2 year warranty is available for $2,700 shipped.. The Cobra outdrive itself has a few different variations, but for the foreseeable future  parts should not be a problem,, I even saw a totally rebuilt  unit from a dealer for 2K$ on ebay.. Used ones in good shape seem to be common and very  reasonably priced ... Yes the Merc is more common, and considered more desirable, but  unless both the engine and outdrive are shot why  replace everything?  First thing I would do before I spent a nickel "upgrading" is finding out exactly what I was dealing with concerning the condition of the engine and outdrive already installed.

The GM 4.3 was actually a VERY good very reliable engine used in pickups, SUV's for many years.

oh and by the way,The Merc 4.3 and the OMC 4.3 are the same engine at heart, a plain old  4.3 chevy.  

Find out whats good before you do anything, and then consider simply replacing bad components after that...  Both the OMC  4.3 engine  and the Cobra outdrives are  readily available rebuilt and suprisingly cheap...

Edited September 13, 2022 by bulletbob

[sherman brown]

I have to totally agree with bulletbob on the 4.3 motors being the same motor. just the outside of the motor is a little different. but the bare long blocks are the same. and yes, they are a very good dependable motor. but i would fully check everything out before doing anything. the 1st thing i would recommend doing is turn the motor over a few times if it's not locked up or won't start then i would do a compression check to see if it has good even compression. if you have 1 or more cylinders that's much lower than the rest then i would look at having it rebuilt or replacing it,.

 

if I were replacing it, I would check eBay if looking for a used engine. and I would want to know the compression on the engine. if I wanted a better engine, I would go to michiganmotorz.com and get a new vortec 4.3 base engine and a 4-barrel intake and carb and any other things I needed to make it work. I think with your older motor you would have to get an intake and electric fuel pump to make it work for you. but you can save a few hundred by getting a rebuilt but then you would only save about 325.00. you can also look on eBay for older engines that's a direct replacement for your year boat.

[HB2]

I had a 1986 230 hp OMC cobra .And I owned it brand new and sold it last year .  

 

Other than the fact I had to have the outdrive rebuilt after a ton of hrs, it was fine . 

Edited September 13, 2022 by HB2