OMC Cobra Lower unit replacement

[jgomez58]

Before I start, let me introduce myself. I am a military retiree (Army, 25 years) and a fully retired hospital administrator, which means I have lots of time to do the things I enjoy. I live near the Thousand Island region in upstate NY. I have owned this boat for 10 years without any problems through routine maintenance, storage, and winterization. It's a 1987 Bayliner Ciera Sunbridge 2450 5L4v GM 230HP w/ OMC Cobra Sterndrive 984542; OMC Cobra 504APARY T0960939; OMC Drive Systems 984757 T0051166. I am having a problem understanding all these numbers pertaining to the sterndrive. My lower unit somehow broke and I am being told that the lower gears are damaged and that it would take $4-5k to fix. At that rate, I would like to replace it myself but I am at a complete loss as to which are the numbers I need to be attentive to, so the right parts can go into it. Any help--besides asking me to dump the boat, which is in pristine condition, is not helpful. I know the story about OMC and its parts, but truly, it is a beautiful boat that I would love to keep enjoying for another 10 years, at least.

 

[nnl1987]

On my omc cobra it still has a metal aluminum plate that's riveted onto the stern drive. Start with looking for that. It's about 2"x1".

You will need some specialized tools to take it apart but it is doable.

 

[racerone]

Try-----kingspropeller ----In Ontario.----Might find a used unit there.

 

[Scott Danforth]

Find a complete 1992 or later Mercruiser 5.7 and Alpha 1 Gen II and swap complete

 

[Lou C]

You can leave most of your transom mount in place & swap to a 1994-2005 Volvo SX.

 

[Lou C]

And, the even cheaper alternative is the SEI Cobra to Alpha conversion.
The conversions make sense if the engine & transom mount & transom itself are in good condition & don’t need work. This saves a lot of labor cost if you can’t pull the engine & transom mount yourself.
As for me I’ve had one 20+ years & had very good luck with it so if I can get my spare drive rebuilt for a reasonable sum that’s what I’m doing. To me it’s a known quantity.