Confused on oil mixtures.

[mettyfish]

In reading some old posts I am getting a few conflicting stories on oil mixtures. Can some of you experts give some details as to oil mixtures that go with what years of motors. I kniow that ratios changed in 64 from 24 to 1 to 50 to 1. But what did the 50s motors run on. I have been running 24 to 1 but have read some posts that say 16 to 1. Confused, Help. Thanks, Mettyfish

 

[HighTrim]

Re: Confused on oil mixtures.

It is well explained in the FAQs, to save me from writing it out here.

 

[HighTrim]

Re: Confused on oil mixtures.

here it is here...

http://forums.iboats.com/showthread.php?t=158072

 

[ezeke]

Re: Confused on oil mixtures.

http://www.evinrude.com/en-US/Owners-Center/FAQ/OilAndFuel

 

[tx1961whaler]

Re: Confused on oil mixtures.

Yes, some of the 1950's motors did originally run at 16:1.
Here is the current recommendation from Evinrude (now BRP):
- What is the fuel/oil mix for my motor?
The following is generally true: 1958 and prior used 20:1, 1959 thru 1963 used 24:1, 1964 and newer use 50:1. High performance usage (racing) requires a ratio of 25:1. New engine break-in (not DI) requires 25:1.
http://www.evinrude.com/en-US/Owners-Center/FAQ/OilAndFuel

Note that the new 20:1 recommendation is for the old 16:1 motors.

Now, there are some 1964 and newer motors (little ones) that I still would not run at 50:1, even though that's what they came out of the factory to run on.

 

[HighTrim]

Re: Confused on oil mixtures.

Agreed that the websites reccomendations are not set in stone. I met an older gentleman that was an OMC engineer back in the day, and during a discussion about this very topic, he reminded me of the start to the Answer in that FAQ on the BRP site, "The following is generally true".

The discussion was generally about the "jeweled motors" '60-64 vintage, 18hp and bigger. He, like Chinewalker in the FAQs, said he runs his at 40:1.

Much smarter man than I will ever be, and seeing as how he helped design the damn things, Ill take his word on it, lol.