Running 24:1 Gas mix in a 50:1 rated motor

[Detri Mental]

Hello everybody,

I have an old 1951 Johnson 5hp TN-27, and a newer 1982 Johnson 4hp. I would like to run both engines on the same trip and for the sake of simplicity just keep one tank of fuel mixed up on hand.

Is it okay to run the 24:1 fuel that my 1951 motor requires in my 1982 motor that calls for a 50:1 mixture? Will the extra oil gum or foul anything up?

Thanks much,

Robert

 

[CATransplant]

Re: Running 24:1 Gas mix in a 50:1 rated motor

You'll be fine. The 4hp will smoke a bit more, but you shouldn't get any plug fouling or anything like that, as long as you have the right plugs in the 1982 engine.

I wouldn't do it for the long term, but it doesn't sound like you have that in mind.

Too much oil isn't a big deal. Too little is.

 

[wbeaton]

Re: Running 24:1 Gas mix in a 50:1 rated motor

Ditto. You could also gap the 4 hp plugs .005" bigger to avoid fouling.

 

[coolguy147]

Re: Running 24:1 Gas mix in a 50:1 rated motor

maybe do a more decarbs for both engines. it will help also. and keep extra plugs maybe just in case

 

[Detri Mental]

Re: Running 24:1 Gas mix in a 50:1 rated motor

Thanks for the advice everyone. If I do go this route I will report back here after a season with my results.