4.3 L OMC Engine to Mercruiser Outdrive

[BiggFrizz]

This may be a stupid question, so please forgive my ignorance. I recently bought a 1988 20' Sunbird Cuddy Cabin with a 4.3L OMC Cobra. The first time I took it out on the water, the upper unit of the outdrive failed and I suspect that there may be problems with the lower unit. When I ran the engine on the hose at my house, I had trouble shifting into reverse (a grinding noise and the whole boat shook). The engine runs great and I was wondering if you can mate an OMC Engine with a Mercruiser outdrive? Also, could the trouble shifting into reverse be caused by the upper unit, the lower unit or both? Thanks in advance.

 

[Lou C]

Re: 4.3 L OMC Engine to Mercruiser Outdrive

You can't just bolt on a Merc outdrive, but one can be fitted with a LOT of work, you would have to change the opening in the transom, and change the steering and trim system, a lot of $$ You can replace the Cobra with a Volvo SX drive, it is more $$ than replacing with another Cobra, but maybe a better long term bet. See my responses to the poster changing a Cobra for a Volvo SX for more info.

 

[BiggFrizz]

Re: 4.3 L OMC Engine to Mercruiser Outdrive

Lou C, thanks for your response. Would the Volvo SX bolt on just like another Cobra or would I have to have do some fabrication to the transom? The whole reason why I was looking into an OMC alternative was because I've heard a lot of negative things about OMC, not to mention the fact that they are no longer in business. Is it still possible to buy new OMC outdrives or would I have to buy a remanufactured unit. Thanks again.

 

[Lou C]

Re: 4.3 L OMC Engine to Mercruiser Outdrive

You can still get parts, and some Evinrude/Johnson dealers will service them too. The cheapest alternative is to get a rebuilt Cobra and have that installed. There is a place in Canada that sells a Volvo Penta kit to put the SX drive on, but it is not cheap. Look for the post in the I/O forum about the guy changing a king cobra to a volvo sx, all the info is in there. If the Cobra is rebuilt correctly and the shift cable is kept adjusted, they are really not that bad, plenty of them are still around and running well.

 

[a.d.mobile]

Re: 4.3 L OMC Engine to Mercruiser Outdrive

The only thing wrong with a cobra, is not everyone can fix them. the upper problem probaly started with improper lube fill. you drain from the lower plug and fill from center plug till it reaches the dip stick on the upper. hard shifting might be a bad esa module or bad shift cable. omc cobra shifts checks should be done with engine off. shift into gear prop should be locked in both directions. for fwd and rev then lake test. if shifting is still rough see if interupter is working, if it is cable might be bad. sorry about your upper! 1 more question is the cable that goes to the drive black? 1988 had a few cable updates to be done

 

[tylerin]

Re: 4.3 L OMC Engine to Mercruiser Outdrive

Check to see which cable you have (red or black). Recall on the black one. I"ve had the cobra for 16 yrs now w/ very good service. Have that one gone through and then take care of it. Your cheapest bet. You try to put a mustang motor in your camaro, you better know what your doing

 

[EricYourHost]

Re: 4.3 L OMC Engine to Mercruiser Outdrive

Hey I have had the 4.3 GL OMC and I went to a guy that is in So. Cal that knows the boat well. I have learned allot about the shifter cables. Mine was replaced 2x before I got it and it really takes a pro to adjust it. When you put it it gear or give it gas, you need to kind of move it into gear and do not ease it into gear as it will wear the knuckle gear. You actually dropping it into gear and meshing the gear and the drive is really not too swift so i just got used to hearing it make a little noise. That is normal for the older boat. Reverse, well that is a different story. You must make sure everything is timmed correctly and that the reverse micro switch on the shifter by the carburator is kicking in. It basically stopps the engine so the gear will drop in smoother. Otherwise it will make a horrible noise and you will ruin the knuckle gear. The boat if tuned properly runs like a swiss watch and your gas will go longer than any other boat of it's stature.
I posted a question about Hydrolock.