GY6 sputtering still even after new muffler.....

Ok, well, as the text says. I took the muffler off last week and ran the scooter around the parking lot to see if the sputtering and quitting stopped. It was maybe a tad less, but not by much, still not street-rideable. So I figured "Whatever" and replaced the muffler anyway. Same thing. I've recently replaced the variator, plug, coil, petcock and fuel filter. It does idle smoothly though, although only for maybe a minute before it died. All lines tested as being clear. im thinking it's got to be the carb.Just bugs the hell out of me that it's so easy to work on a cheap GY6 scooter, yet I've replaced the relevant parts and it's not clearing up. Whatever, most of that stuff needed to be replaced as a matter of maintenance anyway. Thoughts? Thanks.