Very true about losing power now matter what method you use to lean out the engine. Even O2-sensing fuel injector engines still lose the same kind of power. It is just that they don't have the fouling issues due to incomplete burning of the fuel. Lack of oxygen is lack of oxygen. It is going to take more engine of whatever it is to accomplish the same thing at lower altitudes.
I remember trying to get my ATV, rejetted for about 9,000 ft, to the top of Flag Mountain with the air box cover off, peeled off all of the extra weight I possibly could, and almost had to put one foot on the ground pushing the last few hundred feet. There just wasn't much O2 there for the engine to work with. The guys in our group that didn't have as much trouble had engines in theirs that were 50-100% larger than mine. The one that had the least trouble even though he knew he was way down on power, had a new model with specific O2-sensing EFI. That was NICE machine. Anyway...back to our regularly scheduled program...
