Oil Mix Ratio 1975 25 hp Evinrude

[MarkAB]

Just to check if the ratio is 50:1. I know some motors from the 70's were 100:1.<br /><br />Thanks in advance.

 

[OBJ]

Re: Oil Mix Ratio 1975 25 hp Evinrude

Yep....50:1 Mark. Even if ya' see an engine marked 100:1...run it at 50:1. It'll last longer.

 

[MarkAB]

Re: Oil Mix Ratio 1975 25 hp Evinrude

I ran my 72 Yammie 8 at 50:1 for a while. A gunky oil mixture started to drip out of the exhaust ports. When I had it serviced the mechanic said it was running too rich. I have read posts that advise against running too rich, cloggs up the plugs and reduces power?

 

[OBJ]

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.