One lesson learned here is if you heard the engine in distress as in "it slowly died out", you should have shut it down and checked things out. I've seen guys with glow engines take off, and I can hear the engine isn't happy because it's lean, they slowly lose power, but KEEP FLYING, and then when it finally deadsticks, they wonder why. Listen to your engine, it'll tell you whether it's happy or not.

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I definitely agree with Lou that 50 to 1 is not enough oil mix for Lawnboy, but also agree with tkg about those "pre-set needles". That is more likely the culprit for your too lean and hot running engine. Even though you do it a lot less often with gas engines, you STILL have to set the needles for conditions where YOU are. there's no one size fits all. Open them up 'till they blubber like tkg said, then let the engine tell you how far to lean them down.