1985 johnson fuel mix

[stephenb]

I just purchased a 1987 Sea Nymph FM 161 and it has a 1985 30HP Johnson and I have used it a couple of times and I mixed the fuel oil at 50 to 1 and then I noticed today that it says 100 to 1 where the fuel line plugs into the motor, is this possible? It does smoke a little more than I think it should but runs great, what is really recommended.

 

[emdsapmgr]

Re: 1985 johnson fuel mix

Late in the 85 model year (1986) OMC came out with the auto-blend fuel tank for low hp engines. It required a special tank. It mixed oil from a separate reservoir in the fuel tank, with the fuel in the tank at 100:1. The engines ran fine on the lean mix, except for one problem. When not run for extended periods, the oil film on the engine internals would evaporate. Engines internals could rust, esp. if left outside in freezing temps. OMC discontinued the autoblend system after a couple of years. Run your engine at 50:1.

 

[stephenb]

Re: 1985 johnson fuel mix

Thanks, very informative

 

[Vic.S]

Re: 1985 johnson fuel mix

I think you will find that 1985 was the year that OMC switched from 50:1 to 100:1, later changing back again.

Without doubt you should be using 50:1. The old 100:1 label should be removed.

 

[ianbze31]

Re: 1985 johnson fuel mix

Hi StephenB. I have the same motor as you (at least mostly - 1985 30 HP Johnson) and am about to rebuild my carbs. Any experience in that area?

IanBze31

 

[Scaaty]

Re: 1985 johnson fuel mix

Late in the 85 model year (1986) OMC came out with the auto-blend fuel tank for low hp engines. It required a special tank. It mixed oil from a separate reservoir in the fuel tank, with the fuel in the tank at 100:1. The engines ran fine on the lean mix, except for one problem. When not run for extended periods, the oil film on the engine internals would evaporate. Engines internals could rust, esp. if left outside in freezing temps. OMC discontinued the autoblend system after a couple of years. Run your engine at 50:1.

This isn't a A/B motor (least not that I know of), but , that said, not sure exactly the year it started, (had a 84 4hp that suggested 100-1 on the side too). It will work fine if ya never use it. But they recanted a few years later on the gas mixers to go back to 50-1.
Oils got better, but not that much better. Run it 50-1
(Hey La Grange..used to live Riverside and Downers Grove..got out 94)

 

[stephenb]

Re: 1985 johnson fuel mix

My motor only has one carb and I have not had to do anything with it. Sorry

 

[ianbze31]

Re: 1985 johnson fuel mix

Just a note here. The specs in the back of the Seloc manual I was reading as I did the carb rebuild says that the 1985 30hp ratio is 100:1. I know that I've run mine at 50:1 for that last two seasons and it smokes to high heaven. I plan to try the higher ratio next season to see how she fairs. Best of luck with yours.

 

[Tinman57]

Re: 1985 johnson fuel mix

I just purchased a 1987 Sea Nymph FM 161 and it has a 1985 30HP Johnson and I have used it a couple of times and I mixed the fuel oil at 50 to 1 and then I noticed today that it says 100 to 1 where the fuel line plugs into the motor, is this possible? It does smoke a little more than I think it should but runs great, what is really recommended.

I had a 1986 25 hp Evinrude (essentially the same motor as yours) that had the 100:1 sticker on it. I ran it for 16 years at 100:1 and never had a problem. It had 2000 hours when I sold it, and both cylinders had compression of 110. I was unaware of the change to 50:1, but it did not seem to hurt.

That being said, I would recommend using 50:1 in your motor, just to be safe.