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I do not know of anyone using 10:1 or 12:1 at this time, so that is moot.
32:1 is essentially 3% oil ... 25:1 is 4% oil ... 50:1 is 2% oil .... the difference between 4% and 2% is virtually undetectable in both mixture strength for fuel/air and pouring viscosity
TRY IT and see, DON'T just guess or assume
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I do! & have.
Fully synthetic has sometimes required a smaller jet.
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Ignoring viscosity issues does the following add up?
lets say you have gone from 50:1 to 25:1, (2% to 4%)
Therefore you have lost 2% of the fuel as it is now oil.
Just to compare the difference.
( assuming OMC C jet as in twin barrel, so size is number in thou)
There is a 1.67% area difference between a 060 and a 061 jet all things being equal the change of oil ratio from 2 to 4% has made a bigger change than one jet size to the mixture.
( anyone know the theory for flow in a pipe?)
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Test first the 060 jet with the 25:1 & see if it makes any difference, remember doubling the lube, might colour the plug.
Freds the man to ask, he seems to have tried every permutation.
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How much oil?
Dyno tests clearly show that more oil makes more horsepower. A good 55H was tested at 50:1 and delivered a respectable 39.9 HP. Doubling the ratio to 25:1 delivered a shocking 43.3 HP. We now understand why - the reasons apply to all two-strokes. Why do you think ratio makes a differece?
Also, the discussion about jet size -vs- oil ratio is dizzying. Once you settle on a ration and fuel type, the engine will tell you what it likes - provided you don't burn a piston first. Certainly an EGT is a nice tool, but to do it right you'll need one for each cylinder as the OMC triples are actually three one cylinder engines.
Finally, all my engines run 16:1 with Avgas. Why would I pick such a "risky" fuel? There are two primary reasons. There has been lots of discussion: Don't you know Avgas will burn your engine down because of it's high density. Hmmmmm. What gives?
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wowsers so much discussion in my thread all about oil! there has been some good points raised. and some interesting data!:cool:
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Impressive 55H figures Tim, are the test results on the net?
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Mod 50 owner manual, first paragraph, inside cover, 50:1 mix uesin 100-130 octane:eek::cool:
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So what is the reason more oil makes more hp in the 55h...leaner mix?
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compression i would say, lean does not make more power, lean melts pistons.:cool: