OMC to Mercruiser Alpha on a 2556

[allan]

I have done the OMC to DPSM conversion myself. I did not change the transom assembly. I have run the boat now for ten years that way with no problems. The only thing I had to change was the pivot housing and added the spacers in the trim rams. The boat handles so much better. It gets up on plane without having to use full throttle. If I had to do it over again I absolutely would. One of the best things I did to the boat.

[dktool]

Here is the visual of using the Cobra steering fork with the shorter side thrust arms.
Just slightly over 50% of the surface.

[allan]

And like it said been running the boat for 10 years and no problems. The more you dig into the better chances on breaking other things. The next time my engine comes out I will be replacing the whole transom assembly but not necessarily.

[88fourwinns]

I remember discussing that some time back, yet I found it interesting that when Volvo was selling a kit to convert the OMC Cobra to their SX, they made no mention of this and in fact the pix that they showed clearly had the OMC steering fork still installed.

SX_Cobra.pdf (marinepartsexpress.com)

[dktool]

That is a photoshop image, angles are all wrong as well as the representation on the thrust arms.

[88fourwinns]

Cobra Conversion - Sterndrive Conversion Kits - Marine Parts Express
but still not listed in this kit, the part you are buying is the pivot housing which pivots up and down, the engine mounted impeller and the drive
I see your point, it is just odd that neither Volvo nor Marine Parts Express ever mentioned changing that part as well.

[dktool]

As allan stated and is true that it will work with the Cobra steer fork.
To make it completely 100% the fork and shield would need to be swapped.
I would call mine 90% as I didn't swap the shield, but I have all the rest including the sx trim rams.

[88fourwinns]

Believe it or not I’m still running my original Cobra that was on the boat when I bought it in 2002. Very few repairs needed over the years; just a few seals & the tilt n trim hoses. I have a spare drive that I’m going to get rebuilt. Also have a complete spare Cobra transom mount that looks brand new. Cobra parts are pretty cheap.