Converting a 90HP Force to a 125HP

[criddy72]

Hi,
I have a 1991 90HP Force which is a little underpowered on the pontoon boat and has developed a problem in the stator. I have a 125HP force (4cyc) with a broken lower unit. (Friend snapped it off below when was backing boat and hit a cinderblock wall) Can i swap the 125HP powerhead onto the 90HP shaft & lower unit?I have attached some pics of the 125HP as i am unsure of its age but i am suspecting 1989, it ran great and has great compression.
Thanks in advance.

 

[Frank Acampora]

Re: Converting a 90HP Force to a 125HP

Why not simply put the 90 lower unit on the 125 then mount the 125 on the boat? WAY simpler than changing powerheads.

 

[criddy72]

Re: Converting a 90HP Force to a 125HP

Well it is broken off above the water pump on the 125HP. I was mainly wondering if it would bolt up.

 

[Frank Acampora]

Re: Converting a 90HP Force to a 125HP

Same midleg and lower unit were used on those years. The 90 had a lower gear ratio, so you may want to step up 2 pitches on the prop. Other than that, blocks bolt up the same and will fit.
Wow! was your friend doing 95 when he backed into the wall? It takes a lot to break it there.

 

[criddy72]

Re: Converting a 90HP Force to a 125HP

Thanks so much for the info. I dont know what we was doing and i dont think he knew!