Have a 50cc Chinese quad that was running wouldn't idle cleaned the carb out then everything just kept pouring out the overflow so I figured I would buy a new carb Pz16 everything looked the same hooked everything back the way it was before now it won't start feel like it's not get fuel not sure what else it could be. Are the idle screws set from the factory I didn't mess with it

 

i had a same issue, i would maybe check to see if the spark plug is getter spark. To test this unplug the spark plug put it in the little rubber housing thing and ground it to somewhere on the atv, press the start button if no sparks come off then it means your not getting spark, replace it after that it might be something more internal. If my directions didnt help/clear try youtube for how to check spark. good luck!