The 1979 model, 25 hp Evinrude requires a 50:1 ratio, one pint of 2 cycle oil, to six gallons of fuel.
For the 1990 model, 25 hp Evinrude outboard, use a 50:1 ratio, roughly 1 pint of 2 cycle oil, to six gallons of fuel.
25 to 1 is the mixture for the fuel
Johnson engines from 1964 on are a 50/1 mixture requirement. Before '64 they were 24-25/1 mixture. Quite revolutionary of Johnson/Evinrude at the time, changed the industry, everyone followed suit shortly after.
.G Argo Boat Company http://www.argoboat-ny.com
My motor says 100 to 1 right next to the fuel connection....
A 25 hp Evinrude, model number E25RCNB, would be a 1982 year model.
25:1
An Evinrude 25hp outboard, 1985 year model, requires a 50:1 fuel, to 2 cycle oil ratio. This is roughly one pint of 2 cycle oil, to six gallons of fuel.
25
20/1
25:1
Look up and see answer entered for "25 hp Evinrude". It is the same.