Replacing entire OMC Cobra outdrive with one from another boat

[jesse.burrell]

I am new to Iboats forum. I could not find another post on this, so I started a new one. Any help is appreciated. I have a 1990 5.7 OMC Cobra. The Model number is 350APRMED (which when I pull it up in parts shows as a 1989). I ruined the top end of the outdrive by running it low on oil. (My bad). I have priced a remanufactured upper unit and have also looked for a used one (complete) to put on it. I found a pair of OMC outdrives that came off of a dual set up (two 5.7's in Bayliner) I want to make the guy an offer on the one that has the same rotation as mine (right) but want to make sure it will work.
Mine and the used one are both behind a 5.7
Both are OMC Cobras
They have different model numbers (mine - 985689 and his 985273 (did not verify if that was the R or L rotation one, he is checking)
Visually they look identical to me
He said his has the 21:16 gear ratio on the top end
My Owner manual said mine has the same gear ratio
He claims they have been used very little.
I plan to open the top so see the upper gears and drain the oil to look at it for metal filings, color, water etc.....

Will this swap work, Can I assume that one OMC Cobra of the same year behind the same motor will swap with another....?
Thanks

 

[jesse.burrell]

My OMC attached to boat, Used ones shown on a pallet

 

[HT32BSX115]

I ruined the top end of the outdrive by running it low on oil. (My bad). I have priced a remanufactured upper unit and have also looked for a used one (complete) to put on it.

Howdy,

Welcome aboard!
You wouldn't want to just replace the 'upper' though without completely disassembling the original lower since they share oil and contaminated oil that from the destroyed upper will have possibly damaged the lower. running a new upper will just guarantee ruining it in the future.

I have a 1990 5.7 OMC Cobra. The Model number is 350APRMED (which when I pull it up in parts shows as a 1989).

Quite common. Boat manufacturers frequently use "last year" model engines in boats.....

He claims they have been used very little.

Caveat Emptor. Unfortunately, they always say that.

I plan to open the top so see the upper gears and drain the oil to look at it for metal filings, color, water etc.....

Drain them too and inspect the oil that comes out the bottom.........but understand that any used drive may turn out to be "junk" so don't pay a LOT for it.

Your other choice could be a conversion to an SEI or Mercruiser Alpha drive using the SEI conversion. http://www.sterndrive.cc/Cobra-Conversion-Kit.html

Will this swap work, Can I assume that one OMC Cobra of the same year behind the same motor will swap with another....?
Thanks

Yes, any same ratio dog-clutch Cobra will "work".

Regards,


Rick

 

[jesse.burrell]

Thanks for your response. I am going to take a look and offer $800. Hope that's not to much.

 

[HT32BSX115]

Thanks for your response. I am going to take a look and offer $800. Hope that's not to much.

Hard to say. If I was going to make an offer on an outdrive, I would probably want to inspect the oil and maybe pressure/vac check it.

Not sure I would buy a used Cobra for that much though. Paying that much for a used Cobra might make me want to consider a new SEI + conversion.

 

[jesse.burrell]

I saw the link for a conversion kit. Where do I look at a new merc or SEI? Drive? Thanks

 

[HT32BSX115]

I saw the link for a conversion kit. Where do I look at a new merc or SEI? Drive? Thanks

SEI will sell you the kit and you could get a used Alpha or you could get a new SEI drive from any dealer that sells them. I think it's the SE116 drive that is recommended for the kit. It does appear to be about $350 + $1500 for the kit + drive.

But you get a brand new drive with a pretty good warranty. (and you can eliminate that Cobra once and for all) If you're interested in doing this, Ask for feed back in Non-Repair I/O and Inboards from others who did this ........ There's quite a few people here that are happy with the switch..........

 

[Bondo]

I saw the link for a conversion kit. Where do I look at a new merc or SEI? Drive? Thanks

Ayuh,.... Right here,....

 

[jesse.burrell]

So I decided to try the used drive. I bought both of them from the old boat. now I have to figure out which one turns right.
1. Tell me if I am wrong. The shaft out of the engine turns clockwise?? when engine is running (when looking at the back of the boat.)
2. on the shift lever, is it up or down when it is in forward?
If I know these two things I can make sure I install the right drive. Then I will have a good left turning drive to sell..

 

[Bondo]

1. Tell me if I am wrong. The shaft out of the engine turns clockwise?? when engine is running (when looking at the back of the boat.)

Ayuh,..... That's backwards,.... Our motors turn left handed, when viewed from the PTO end,.....

Clockwise from the pulleys end,....

 

[jesse.burrell]

Thanks again for helping me out. I pulled the top of the outdrive and turned the engine over and found which way the engine turns, then came back and read that you answered my question I also found out that both of the outdrives I picked up are the same, normal, rotation. I had to switch some little plastic plates on the sides and the anti corrosion thing over as the new, old drives did not have one. so....I hope I am good to go as soon as my gasket comes......
Thanks,
'I will update this in case this thread helps someone in my same predicament.

 

[HT32BSX115]

Hope it all works out! Let us know how the installation and operation goes!

BE SURE you refill the drive you use correctly and in accordance with the OMC service manual instructions. (I.E. DO NOT fill from the bottom, drain port!!)

 

[jesse.burrell]

Success. I was able to get a gasket, mount the "new to me" outdrive and put my prop on. I drained the outdrive and put now gear oil in. Also put a new impeller in. Things seem to be good. Thanks