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Perfect Nihaomike, I'll look into it. I'll need some that have a reasonably high output.
dan, You're right det is caused by a pocket that fails to ignite with the rest of the cylinder but in my experience most of the time when det is really hammering it out is when the cylinder is too rich. It simply just doesn't have enough air in the pocket to overcome the octane rating and the pressure. It can happen under any circumstances, if the pressure gets great enough fast enough it can trap the fuel in a high pressure state until it detonates when the temperature continues to increase.
Pre-ignition is what toasted me. It toasted me from the amount of heat being output during lean burn without being regulated.
I disagree on the AFR. Honda, Toyota, Ford, GM and others have all built mule engines that can do better than 35:1. Not only that they can do it without suffering diminishing returns. The problem with typical engines that go lean. . .is they go lean with very very little fuel to start with. I'm trying to create the amount of fuel you get at say 2000 TP 24% with the amount of air you'd get at 2000 TP WO. The problem and the reason you can't traditionally go much higher than 20-25 is. . .they kept the same amount of air and dropped it to a marginal amount of fuel. The small engines use less than a drop of fuel per injection. If you lean it out at 2000 rpm. . .your banking on pure dumb chance that the fuel is going to be near the spark plug. The fuel ignites just fine in lean conditions if the probability is high enough that there is fuel near the spark plug. With a normal cylinder full I haven't really had problems, not to mention the fact that the O2 air mixture has a lower octane rating than gasoline in those volumes and with the additional heat stored from each combustion event.
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