OMC Cobra to Mercruiser conversion

[Tim Bromund]

Hi guys, how big of a job/hassle is it to convert a boat from an OMC Cobra to a Mercruiser I/O? Thanks

Tim

 

[sugilbert]

Google: omc cobra to mercruiser outdrive conversion

There are 3 9-10 minute videos on it, plus 1 from SEI

 

[Tim Bromund]

Thank you

 

[alk]

I had a bayliner with an omc. When the drive failed I looked into a conversion and decided to just sell ( give away) the boat.

I dont remember the specific details, it was almost 20 years ago, but I remember thinking it was way too much of a hassle. I think an omc to volvo swap is easier - but then you have a Volvo, which sort of has the same issue as OMC - next to impossible to find cheap aftermarket and used parts. But of course at least with Volvo you can find new parts and a dealer network. Have to say, before my cobra failed, i thought it was an awesome drive.

 

[LouC]

you have a few options,
one is the SEI Cobra conversion, probably the least expensive, but the SEI drives have spotty reliability
the next is the Volvo SX conversion, this is more expensive by a lot but about the same amount of work and gives you the much stronger cone clutch drive, I looked into doing this and it was closed to $5000 using used parts and my labor
next is to replace everything with Mercruiser, proably cheaper than the Volvo conversion due to more used parts out there but the engine and entire transom mount has to come out. OK if you will keep the boat a LONG time
last idea, that I thought of was to use the SEI coversion kit but get a used or rebuilt genuine Merc drive instead of the SEI copy.
Me, I am still running the Cobra, liked enough I bought another good used one as a spare. For less than half the cost of a used Volvo SX drive I was able to buy a used 4.3 V6 Cobra drive, complete transom mount, Y pipe, steeing actuator etc. Cobra parts are well priced now if you know what to look for and can adjust the shift linkage yourself.

 

[Tim Bromund]

Thanks for the input guys, I have a 1989 22’ Starcraft Islander Hardtop with a 4.3 OMC Cobra. The boat has sat in my yard for 5 years and in that time, the wood structure in the transom went from a little punky to completely shot. Since I’ll have to remove the entire drivetrain to replace the transom, I thought it might be a good time to swap out the OMC with a Mercruiser while everything is out. I was curious how involved the outdrive swap might be.

 

[LouC]

If you have to re-do the transom, then converting the whole thing over to a Merc Alpha 1 Gen 2 makes the most sense, that way you have something any mechanic can work on, parts are everywhere etc. I kept the Cobra because I found it very reliable for me even in 100% salt water use but to be practical, that's your best choice. I would see if you can find a later model boat that has a rotted structure but the mechanicals are good, or a insurance salvavge boat where the hull is damaged beyond the value of the boat, this way you get all the small bits without having to buy them individually.

as far a doing the transom and locating the cut out for the Merc drive (the OMC Cobra, Volvo SX and Merc Alpha all use the same cut out) I'd go over to the restoration forum on iboats.com and ask , there are people there who know exactly how to do it right the first time.

 

[Tim Bromund]

Thank you, I’ll do that.

 

[ddurand]

Unless you really love that boat time to move to a newer boat.

I had a 1987 Cruisers Inc 24' and I put a lot of effort into maintaining it. But there was just always more to do. It was never going to be as nice as a newer boat. I donated it to Boat Angel and bought a 2011 boat.