15" lower on 20" mid

[rekcuftar]

With respect to the 3 cyl omc's. If you wanted to run a 15" nitro foot on a 20" midsection what would be the smart way to get the correct length drive shaft?

[Fast Fred]

i don't think they make said shaft, you could make an extension for the drive shaft.

[rekcuftar]

How would you combine the 15" lower with the 20" upper? I know Tim Sharkey had a 20 mid on and sst60 on his boat. What is the accepted way of doing something like this. How would you go about making one Fred?

[Fast Fred]

i would do it like i've seen on a merc V6, just extend it. drive shaft holder tool, used drive shaft with the right spline. weld the used shaft to the tool, take the time to make it nice, strong, spins true, the right length. just drop it on. you could tack it, no tack welds on the merc set up.

[rekcuftar]

Thanks Fred I had know idea how it was done, If I chose not to tack it the lower would still have value to a short shaft user.

[Fast Fred]

oh,your goin to want that 20" shift shaft, just spin it in to the 20" hight adjustment. that should do it.

[sharpeye Mike]

I bought a 15", 75 hp stinger from a machinist who turned it into a 20", he made an extension for the driveshaft, water pipe, shifter rod, even the mid was extented and all bolton. Is the nitro gearcase bolt patern the same as a 20"?

[rekcuftar]

My understanding is that the bolt pattern is the same. But it the bigger clunkyier v4 foot that came on the 20" mid. Which is what mine is. The short shaft had the smaller 2cyl foot with a taller gear ratio.