fuel oil ratio

[perceyg]

I just bought a 1966 20hp johnson outboard motor and need to know what the fuel mixture ratio should be. I found 10 articals online 5 say 24-1 the other 5 say 50-1 anyone really know. HELP PLEASE. THANKS

 

[wilde1j]

Re: fuel oil ratio

If the motor has sleave bearings, 24:1, if needle bearings 50:1.

 

[Vic.S]

Re: fuel oil ratio

The official line from Evinrude is that from 1964 onwards motors can generally be run on 50:1

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

There are some motors, those which do not have needle roller bearings thoughout , which are better run on a more oily mix. 24:1 in some cases. They are mostly the small motors AFAIK.
(There are undoubtedly also older engines that could be safely run on 50:1)

The parts diagrams for your 1966 20 hp shows that it has roller bearings throughout. On that basis there is no reason to run on anything other than 50:1.
SEE HERE

 

[F_R]

Re: fuel oil ratio

It is supposed to be run on 50:1. No mystery. End of story.

 

[perceyg]

Re: fuel oil ratio

Thanks to everyone for your help!