Can I change from triangle coupler to "Hub" style?

problemhouse

Recruit
Joined
Jul 25, 2017
Messages
2
I just purchased a 1989 Baja Islander with a 3.0l and Mercruiser Alpha 1. The coupler was bad when I bought it and I just took it out and see it is the triangle style coupler. (12632A7 or Sierra 18-2195)
It is much more expensive to buy this coupler than it is to buy the "Hub" style coupler (76850A2 or Sierra 18-2171)
I have read posts about changing TO the triangle coupler but not posts about changing FROM the triangle to the hub. Is it possible to do this with little or no modifications?

If not, I see the kits for the triangle style come with the splined shaft, whereas the hub style do not. Is it imperative to get a new shaft with the new coupler even if my shaft looks good?

Thank you,

- Jason

Outdrive = C586554 (all that is visible)
Engine = 0C522473 Model MCM 3.0 L 130 HP LH rotation
Transom = 0C637934
 

kenny nunez

Captain
Joined
Jun 20, 2017
Messages
3,462
Mercruiser and the other users of GM blocks went to that style because of the smaller bolt circle on the crankshaft. There are a few earlier models that had the larger bolt pattern with the triangular coupler. This could be because the engine was replaced at some time. Stay with the design that you have.
Also you need to inspect the transom for flexing and the front motor mount for the wood getting soft. Pull the engine and replace the rear motor mount bushings in the adapter housing. Then get the alignment straight with the alignment tool.
 

problemhouse

Recruit
Joined
Jul 25, 2017
Messages
2
Thanks for the response kenny,
I do have the motor out. Not sure of the history or what all might have been done to it. I was planning on getting some 1/2" longer lag bolts for the front in case the top section was soft and then the bolts could reach deeper better wood. (1/2" wont go too far through) The rear bolts were TIGHT and the floor seems great. (not soft) Overall the boat is very nice and appears well taken care of. I do need to get me one of those alignment tools for re-installation though. Was going to order that the same time I ordered the coupler. Was just hoping to be able to use the cheaper coupler to save $
 
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