Me too,we're both in the soup I guess .
Then again being a dumbazz somebody is going to have to explain to me how running a richer oil mix could cause a lean burn .If that were so I'd have thought those old Johnson and Mercury boat motors would have seized up.How they ever kept running for 50 some years remains a great mystery .Oh not to mention ,right from the book on McCulloch go kart racing engines they recommended 20 to one .How is that so ?BTW that was racing oil not SAE 30WT .
Because first off, those engines were designed and jetted to run that mix ratio. Not to mention carbs on those old outboards were infinitely adjustable, and easily done on the fly to boot. And secondly, they were not putting out high HP per CI or CC, in other words, they weren't very high strung performance engines..a bit more forgiving. Maybe not so much so compared to chainsaws, but compared to modern sleds, jet skis and others that still run 2-stroke engines they much less high strung.
To better explain why I stated that increasing oil in your premix will lean
combustion mix:
First we have to understand what purpose the premix oil serves. That is to lubricate all of your major moving engine internals, IE crank bearings, rod bearing, wrist pin, and cylinder wall. It does not accomplish this if it is all taken into the combustion chamber and burned. Most of the oil is intended to and does fall out of suspension with the fuel charge once it is taken into the crankcase. And when it does it coats everything inside the crankcase with a thin film of oil, mission accomplished,the oil has done it's job at this point. This happens with every intake cycle. Yes some does make it's way into the combustion chamber along with the fuel mixture, as evident with that wonderful smelling blue smoke. This is mainly an unavoidable side effect, not a desired effect..at least with most common 2-stroke tech and designs that we have today..But it is getting better with stratified and direct injection 2-stroke engines...
Now, the reason most people have it backwards when it comes to the relationship between premix ratio and combustion mixture. Most mistakenly think that more oil in the premix will make the engine inherently richer..well, in a minor sense it does, but only in terms of bottom end lubrication and emissions in the form of oil smoke. What I am talking about is actual combustion mixture, the blend of gasoline and air needed to ignite and drive the piston downward. This mixture is directly related to the life of your engine and how it runs. Too much fuel and it will run, down on power but won't hurt a thing. Too little and she burns down due to too much heat being generated by the higher amount of oxygen compared to fuel. We've all seen lean burn-downs and what evidence it leaves behind.. Now consider this, your fuel circuits are only so big and only a certain amount of fuel/oil mix can pass through them at any given time. When you add MORE oil to your fuel premix, what happens to the amount of fuel you are delivering to your engine for combustion if you do not make adjustments to compensate?? Answer: It is
reduced. Now, I am not saying a burn down is guaranteed if a person goes from 50:1 to 40:1 on a stock saw that is not tuned to the ragged edge for performance. But what I am saying is that you are in fact leaning the fuel mixture for combustion, and in some cases of highly modded saws, or saws hat are kept tuned to the ragged edge, one could very reasonably expect to experience signs of at least a minor lean condition. Take things to the extreme with modding or big changes in premix ratio, the results will coincide.
Hope that helps you to understand.
