mercury lower unit 1965 65hp

[saratogalake]

I need a lower unit for a 1965 65hp mercury 4 cly. I am trying to find what years and what hp units will fit. looking to find a chart that will show which units will interchange with it.

 

[Chinewalker]

Pretty sure only other 4-cylinder 65hp lowers will fit. The 65 was kind of an odd duck in that regard... Not even sure which years of 650s will fit, as they built them for almost 10 years and changed a few things along the way. The 3-cylinder 650 lower units will NOT work.

 

[jimmbo]

The 4 cyl 65hp used the same gear ratio(2.3:1) as the 4 cylinder 75, 80, and 85hp models, if the crankshaft splines were the same, these would work

 

[Chinewalker]

I believe the housings were different going back that far. The first big 66-cube 4s didn't come out until the late 1960s.

 

[jimmbo]

The 4 cylinder 65 used the same props as the inline 6s so the housing should be the same

 

[Chinewalker]

Okay. Deferring to Jimmbo on this one...