Exchanging newer outdrive with older?

[Mr-Moe]

1980 OMC 400 has been run with water and little oil in the outdrive.
some bearings have seized in the outdrive upper section.
Have access to an older outdrive from a 1969 unit. Will the ‘69 outdrive fit the ‘80 midsection?
Question two, how common is the OMC 4 cylinder with twin carbs?

 

[kenny nunez]

The 69 model drives only were produced in one length which is 4” taller than the 400 model. The upper gear housing internal gears and bearings are the same if the 69 model was used on a 120-155 hp model. The water pump and pinion shafts are also longer on the 69 model.
And of course the 400 is a mechanical shift and the 69 is electric shift.
The 120 twin carburetor Models were plentiful but had to be synchronized or they would not idle good. When they were running good they were the quietest and smoothest running packages. The last twin carburetor models were produced in 72 then the 2 barrel low profile models started in 73.

 

[Scott Danforth]

No....it wont fit.

Your 78-80 hydro-mechanical drive can be changed with a 81-85 mechanical shift 400