1970's 120 mercruiser outdrive 1.98 gear ratio vs. 1.50

[Lowchopr]

hey guys, hope everyone is having a great weekend, took my 120 mercruiser 18ft beater out today, would not plane, i have installed a backup outdrive with a 1.50 gear ratio {sn 3133093} outdrive beacuse my 1.98 was not shifting at all, im wondering if there is any prop that will work with this combination. thanks in advance.

 

[Bt Doctur]

Don`t think there`s a prop small enough

 

[Lowchopr]

I think I'll just swap the lower units.....

 

[Lowchopr]

Anybody wanna trade a 1.98 for a 1.50?

 

[achris]

Use the old (1.98) upper and the new (1.5) lower. The ratio is in the upper, the shifting is in the lower.

 

[Bt Doctur]

If your old upper drive is an 8 spline, a newer lower wont work