got to be fuel, is there a smell of petrol in the bore?
I know you said you cleaned it, but did you strip down the carb into parts and use an ultrasonic cleaner? this is the best way to ensure its clean. I hope you checked fuel flow first.
drewps
cool pepps
is it the 3n7 model with isolated engine mounts?
get polishing thoses engine cases
BTW I put the pikkies on here in case you though it was for forum pixies