Jack plate and older style merc mounting pattern

[harleyguy302]

Have a question. I have a mid 80's ranger I bought with a blown motor. I sold the motor and was planning on putting on older 90 hp merc on it. So this weekend I was looking at the jack plate on the boat and noticed the older merc has the old style mercury mounting holes (roughly 8? apart). The original motor had new style mounting pattern. So I did some measuring and the old mercury mounting pattern will not reach the jack plate. It fits right between the two pieces of angle iron. So my question is has any one ever made a plate or something to bridge the gap to mount this older style to? I was thinking about bolting something between the jack plates (wood or steel) using existing bolt holes. This way I could remove and use original holes if I were to upgrade motors down the road. Any suggestions would be appreciated.

Thanks

 

[roscoe]

Yes it has been done.
I would weld it in.

 

[sludgeguy68]

The PO of my boat had a similar problem and simply didn't use all the bolt holes to mount it, which eventually resulted in snapping the clamp and trim brackets on me while underway. I just drilled two new holes into the jack plate where it didn't line up when I replaced the mounting hardware.

 

[harleyguy302]

Looks like I'll make something to bridge the gap. What would be material of choice? I'm thinking 3/8" aluminum plate right now. Or maybe 3/4 plywood stacked to 1.5" thick.

 

[Chris1956]

I used a two piece jackplate on both an older inline six and a newer V6 Merc. I had originally installed the IL6 motor on the Jackplate. A few years later I replaced the IL6 with a V6, with the newer 4 bolt pattern.

The Jackplate halves were just wide enough to allow the bolts from the bottom of the IL6 motor, and the bolts from the PTT brackets of the IL6 motor to be used (with new drilled holes). If I remember correctly, I needed to redrill the the boat transom, when I installed the V6 motor. I used a piece of plywood between the two jackplate halves, to give the thumbscrews of the IL6 motor something to clamp.

So if you have the two piece Jackplate, you would need to fill and redrill the transom bolt holes, to allow the IL 6 motor to bolt to the jackplate.