I have a 1988 two stroke 70hp Yamaha, with the 2.33:1 lower unit. I would like to run a smaller lower unit with higher gears.

I know that the lower unit from a 55hp Yamaha will bolt up, and has a 1.86:1 ratio. I have read that the lower unit from a four stroke 50 will bolt up, and has a 1.84:1 ratio.

Can anyone confirm that the gearcase from a F50 will fit a 70hp two stroke?