OMC hole size reduction

[79Glastron]

I've been looking for threads about changing a boat from a OMC stringer to a Mercruiser. I'm looking for info on going from the large OMC hole to the smaller Merc hole. I found a guy who used seacast, but he poured a complete new transom and I don't believe I need to do that. What options or procedures have you done? I saw on the seacast site that you can use seacast and keep your good wood in your transom, but the info is pretty basic.
Thanks!

 

[proshadetree]

Re: OMC hole size reduction

The seacast is a good option. I would personally just rip the old transom out and install new wood. Then build the outside where needed and cut out new hole. Sorry not the answer you were looking for. This swap will not be an easy one weekend job.

 

[vi]

Re: OMC hole size reduction

Isn't the OMC transom only an inch and the Merc 2" ? I was thinking you could make and glass in another piece over the existing transom then put the plug in the space where the OMC went glassing both sides? I'm speculating and guessing as I will probable be going down the same road soon...

 

[oops!]

Re: OMC hole size reduction

there is a conversion kit you can buy......

but i would just build a new transom....

to vi.....welcome to i boats...

the omc hole is a totally different and much larger.over one foot wide......to the mercs smaller keyhole shape....they do sell conversion kits....but done incorrectly the chances of leaking are increased....

cheers
oops

 

[Huron Angler]

Re: OMC hole size reduction

http://forums.iboats.com/showthread.php?t=369247

This thread is a 22' aluminum resto, converted from OMC to 4.3L Merc.

There are templates available to get the holes and X dimension correctly cut out.

The thread is pretty long, but has good info.