ORIGINAL: downunder
With jester's engine (the way I read it) he's done the rich break in with no problem starting it. But at the end of the rich running (4 stroking?) he's immediately tuned for just below peak and this is when the problem started. I suspect it's got more to do with the idle setting now.
I suspect a lean idle too.
He went from sloppy rich to leaning the high speed for just off peak. That effected the idle too. But, he's made no adjustment to the idle screw.
Richen the low end 1 or 1.5 turns and see if it'll start.
You can always tell when a glow engine is too lean on the low end. It won't start with a flip. They will sometimes start with an electric starter, and idle okay for a short time-- but when you go to throttle up--they abruptly fall on their face and die. Sure sign of a lean idle mixture.
Most engines are a bit finicky for about a gallon. It takes a bit for them to break in fully and seat in real nice. I set my idle screw for just a touch rich
(maybe 1/4 turn rich from perfect) after my initial break in and fly it like that for about a gallon or maybe 1.5 gallons. Then tweak the low end for absolute perfection and rarely ever touch it again.