Re: Oil Mix Ratio 1975 25 hp Evinrude
If the manual says mix is 50:1, don't run any less. Usually when you see the black gunk running from the exhaust, it means that you probably need new plugs, spark is getting weak, possibly sticky rings and so on. Running any less than what the manufactuers are calling for and you seriously are jeapordizing the well being of the engine.