Lower Unit Options 'Rude 25

[songdog]

I have a 1975 OMC 25 # 255538. We do a lot of duck hunting here in Michigan and the water leveles on Saginaw bay are constantly changing. Impeller lives are short and lower units are sometimes damaged. I would like to pick up a spare lower unit can someone advise on the year and hp ranges that are compatible to me. I know the easy answer is 1975 25 hp.

 

[WillyBWright]

Re: Lower Unit Options 'Rude 25

18, 20, 25Hp from the 60s, 70s, and into the mid 80s.

 

[rodbolt]

Re: Lower Unit Options 'Rude 25

after about 75 the drive shaft splines changed. but nost of the mid sixties to 75 18,20 and 25 units will interchange. some must be swapped as a unit as some of the seals and bushings changed.

 

[songdog]

Re: Lower Unit Options 'Rude 25

Thanx guys my plans are to have a couple fully assembled units in duck camp as well as an extra impeller assembly. Most guys in my area are running 70's OMC's and may appreciate having a spare unit around. Nothing will ruin a duck hunters vacation quicker than outboard trouble. Last week I helped a group of hunters change their impeller "in the field" ie. standing in knee deep water. Don't drop anything!!!