confused on fuel mixture on 25 johnson

[peteman]

well i have a 25 johnson long shaft out board motor,, the manual im not to sure if its the righ year but says 50:1 and on the motor the sticker is 100:1.When mixing i usually mix it 100:1 then just add a little extra of oil just to be sure,now should i be mixing it 50:1?when i add that little extra like 50 ml to the mix it does smoke alot at idle so thinking 50 to 1 would be way to much maybe?it is about a 1989 or 90.I just changed my plug and they are black better than a blowen engine i take it..

any input would be great Peteman

 

[ob]

Re: confused on fuel mixture on 25 johnson

Initially the factory recomendation was to mix 100:1.It is my understanding that the updated factory recommendation is now 50:1 as all other OMC engines of that vintage.

 

[F_R]

Re: confused on fuel mixture on 25 johnson

100:1 was another OMC screw-up, among many. Don:t do it. Use 50:1. If you don't like the smoke, use 100% synthetic TC-W3 outboard oil. It's bio-degradeable too.

 

[steelespike]

Re: confused on fuel mixture on 25 johnson

These motors always seem extra smokey when first started and especially in a barrel. When running right on a boat smoke is not too bad.

 

[peteman]

Re: confused on fuel mixture on 25 johnson

right on ,, thanks for the input.Hopefully i didnt do to much damage,i did mix it 100 to 1 but always added 50 to 100 ml extra just to be safe,i just changed spark plugs and thier where black.Took it out for run and the motor seem s to run fine ,so from now on it will be 50 to 1.

Thanks Peteman

 

[Tinman57]

Re: confused on fuel mixture on 25 johnson

I had a 1987 Evinrude 25 and ran it on 100:1 for 16 years. I was blissfully unaware of the recommended change to 50:1. When I sold it, it had compression of 110, 115. That being said, I would have used 50:1 if I had known.

It was a darn good motor in any case

 

[wbeaton]

Re: confused on fuel mixture on 25 johnson

I have a 1987 20 hp that has always run on 100:1 and never winterised. Still in beautiful shape. Of course, I don't run it anymore and only use 50:1 in my 1988 30 hp.

 

[F_R]

Re: confused on fuel mixture on 25 johnson

At a dealer service seminar back in '64 when the 50:1 oil came out, there was a lot of discussion about how and why that could be done. An Evinrude factory engineer told us way back then that they could run 100:1 in some models, but they couldn't trust the public to measure it accurately or to use decent oil. I believe Scott-Atwater was already running 100:1 at the time??? How many of us used to take a quart of oil and dump in "that ought to be about right" oil and fill 'er up with gas? Or even still do when we have about two and a half gallons remaining in the tank so dump in about the right amount of oil and top it off?

 

[samo_ott]

Re: confused on fuel mixture on 25 johnson

Way back in '64??? FR are you that old?

 

[tashasdaddy]

Re: confused on fuel mixture on 25 johnson

he's older than me, and i'm related to dirt.

 

[BoatBuoy]

Re: confused on fuel mixture on 25 johnson

In '64 I dumped in a quart and a half of oil in a 6 gal. tank because I didn't know the ratio had been changed to 24:1 from the original 16:1. That was for my 35 on an aluminum Feather Craft. And then I was off in a cloud of smoke with a hearty "Hi-O Silver".

 

[wbeaton]

Re: confused on fuel mixture on 25 johnson

I feel like a baby, here. I wasn't even alive in the 60's.

That's pretty interesting, FR. I wonder what models those would have been.

From what I've read on the subject the problem with 100:1 is really more of a storage issue than a running issue. Though, some feel it is too lean at WOT. For the price of oil, I just mix at 50:1 and say why risk it?

24:1 is smokey enough for me. I couldn't imagine 16:1. I tried Amsoil at 24:1 the other day in a 1949 and a 1953 Johnson 10 hp and there wasn't a bit of smoke or oil sheen left on the water. I may be a convert from conventional oil for the old girls. We'll see at the end of the summer (if nothing blows up).lol

 

[F_R]

Re: confused on fuel mixture on 25 johnson

What do you mean Way back in '64? That was the year I got married, after everybody had given up on that ever happening. I was 27 then. I'm not older than dirt, I'm older than the rocks the dirt came from.