Mercury 115 lower unit comatability

[dswanson79]

I need a lower unit for a 1996 115hp 4cyl. long shaft. will a lower unit from a 1996 90hp 4cyl. long shaft work as they look identical? I have heard some people say the gears are different is this true and if so how would it effect performance?

 

[Laddies]

Re: Mercury 115 lower unit comatability

A 96 90HP should be a 3 cyl with a gear ratio of 2.31 to 1 and a 115 has a ratio of 2.07 to 1 it might be possible to over come with a prop change but it could change idle and mid range performance.