repowering from OMC Cobra to Merc or volvo diesel

digitalman

Cadet
Joined
May 1, 2007
Messages
14
I have a 1987 OMC cobra stern with the 5.7 liter V8. I need to repower the boat and dont want another used OMC obviously. Since transom cutouts are evidentally the same for the Cobra, Mercruiser, and Volvo diesels...I am thinking if I stay with gas, putting in a lightly used Mercruiser 3.0 130hp or Merc 140hp..and if I could figure a way to do the diesel..well thats what I would like the most. So a Volvo diesel stern of some kind. Where I live there are quite a few freshwater boats..and I was thinking to pick one up and strip it of necessary drive, engine etc.

Can I get some imput on this? Appreciate it. What issues am I going to have other than the obvious motor mounts and such in the boat receiving the transplant?
 

Steve Mahler

Petty Officer 1st Class
Joined
Oct 10, 2006
Messages
361
Re: repowering from OMC Cobra to Merc or volvo diesel

I assume you dont need the boat to plane anymore, since this will be a big reduction in power.

The 3.0 merc idea is a great one; they are plentiful on the used market, and the re-installation will be easiest. I am not an expert, but I am quite sure you will have to find different motor mounts- but keep in mind several bayliners offer either the 3.0 or the 4.3 - which shares the same block minus two cans - so you might find a used resource digging around bayliner dealers etc.

As for the diesel, google around and you will find folks in europe who convert all kinds of US boats to diesel...looks like a lot of custom fab work, but very cool. I would fear that the cost would outweigh the benefit vs. the easy 3.0 however.
 
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