old evinrude spark gap and oil mix

[44sparky]

i have an old 1954 7.5 evinrude that hasn't been run in years. wondering about the spark plug gap and oil/fuel mix? i know the factory recommends 16: 1 but with today's improved oil, i was wondering if i could go to possibly 25:1 ?

 

[rickdb1boat]

Re: old evinrude spark gap and oil mix

44sparky,<br /><br />NGK Standard Plug-B6S Gap.030 <br /><br />I believe you could run 25:1 with no problem. I have seen on this forum where 32:1 was recommended. You might want to do a Search in the forums and see what others are using. Good Luck,<br /><br /> Look Here

 

[steelespike]

Re: old evinrude spark gap and oil mix

Sparky, Stick with the reccomended mix.<br /> Modern fuel mix recomendations come more from<br /> modern engine technology than oil technology.<br /> If it was my motor I would run 16:1.

 

[Lark40]

Re: old evinrude spark gap and oil mix

Agree with Spike. Read Rickdbiboat's link, but what applies to post-1964 engines does not apply to pre-1957 OMC engines. <br /><br />There was an upgrade from sleeve to roller bearings in 1957, so those engines can benefit from higher ratios. Not so for your engine.

 

[44sparky]

Re: old evinrude spark gap and oil mix

thanks fellas, for all the helpful info. will stick with the heavier fuel ratio. not concerned with cost as much as violating the environment.