How do you know if it's the wrong fuel/oil ratio?

There seems to be a variety of opinions regarding the correct fuel to oil ratio for two-strokes, even among those of us with the same engines. When I ran my Minarelli V1 @ 50:1 it backfired constantly. At 33:1 (as specified in the manual) it runs great. Miguel says his Minarelli runs great at 43:1. I suspect that if we traded fuel, both of our peds would run just fine.

Question: What would be the symptoms of a wrong ratio? Why did the 50:1 cause backfiring? Was it damaging the engine?

And what if my mixture is too oil-rich, say, 15:1? Would it run badly, would it foul the plug, would the machine stink like hell? Anyone have experience with the results of bad mixes?

Re: How do you know if it's the wrong fuel/oil rat

flannelman /

do a plug chop

Re: How do you know if it's the wrong fuel/oil rat

I was under the impression that a plug chop provided information regarding the air/fuel mixture, not the oil/fuel mixture.

Re: How do you know if it's the wrong fuel/oil rat

JD wrote:

>

> I was under the impression that a plug chop provided

> information regarding the air/fuel mixture, not the oil/fuel

> mixture.

That is correct... a plug chop does NOT give you any real info about oil.

Its a long subject JD... and most knowledgeable 2 stroke riders run between 4 and 3 oz of oil per gallon.

Or synthetic at 50 to 1.

The recomendation by the manufacturer is pretty much an arbitrary one... based on how comfortable they feel with their motors reliability and longevity... (and legal strategy for warranty claims).

And of course ... I don't think ANY peds come withOUT oil injection now... just because of all these kinds of questions... and people forgetting to put oil in the gas.

And most of those recomendations were from way back when .. when 2 stroke oils weren't very advanced.

There is really no logical reason for your ped to 'backfire' at 50 to 1... as opposed to 33 to 1.... I bet it was an aberration that would have happened with either oil ratio.

Re: How do you know if it's the wrong fuel/oil rat

Thanks for the info, Fred. I couldn't imagine how the oil ratio would cause the engine to backfire constantly, but it ceased as soon as I drained the tank and put in fuel at the 33:1 (really 32:1) mixture. The oil in the 50:1 mix was a synthetic all-purposes product that came with my new snowthrower. Since I had a big tank fill of the that mixture (which worked just fine in the snowthrower --- as if I would have noticed if it hadn't) I thought I'd try it in the Minarelli. Maybe it was something about the synthetic product rather than the mix ratio.

I'll never know, but I'm sure as heck not going to try it again.

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account