Can I install 1972 Evinrude electric start on 1977 Johnson?

[belmont812]

I have a 1977 Johnson 25hp outboard motor that pull starts. The serial number is 25R77S. I want to add an electric start because it is very difficult for me to pull it. There is a 1972 Evinrude 25hp parts motor for sale close by and I was wondering if the two are compatible for the electric start parts. The 1972 serial number is 25252R. If not, then what years are compatible for a 1977 model? Any information would be helpful. Thanks!

 

[Chinewalker]

No, I don't think it will quite work. The '77 is a 31.8 cuber while the '72 is a 22.1 cuber. Similar starter & bracket, but I think they'll be just enough different that they won't work. You'd need one from a 20-35hp of the 31.8 cube variety, c. 1976 on up into the latter 1980s. Keep in mind, if you get too late in years, they changed he flywheel design and the number of teeth on the ring gear.