ORIGINAL: hsukaria
I've had engines go suddenly bad, it was dirt in the carb. Try pumping fuel through the carb at idle and WOT to flush it out. It helped me.
Good point.
You can push fuel into the carb with a pump directly connected to the nipple, and then quickly reverse it to suck out or dislodge any obstructions.
At worst remove the nipple too and make sure that there are no clogs or debris.