First and foremost, before you start drilling and unscrewing stuff, go for the most simple and obvious, check your gasoline for any sign of water, pull off your fuel line from the carb and drain it into a clear or white bowl, look for the gas to float on the water, I have realized that it takes a good while to run even a tiny blob of water through these carbs to get back upto speed also it is damaging. I ran into a similar issue, It was brand new gas, but I had not purged my "older jerry can" and of course put, put, cough cough, quit quit. After piddling around a while I had to step back and think. If there is any sign of contamination, drain your fuel system and flush it, take the float bowl off your carb, (three screws, one to mount it, two on the float bowl) rinse it out and blow through the venturi. I find these lil Gems almost indestructible otherwise. I have mixed into my fuel some of that space age metal treatment stuff, slick fifty/prolong, ect,I run some through every couple of tanks.