MOPED ARMY

hey Fred, i just brought my moped carb to the shop and had them clean it(the guy i brought it too looks like a really shysti person and the carb looks like it wasnt even touched) the reason i brought it there was because the screw that holds the bowl on is stripped( i cleaned as much as i could without taking off the bowl) anyways i got it back and put it on and the moped runs but runs extremly weird, it starts up and runs but only runs if i have the choke on or will run for a short time and die, and when i give it gas it might go but then it lets off and then it goes and lets off even though im giving it full throttle and sometimes even when i give it gas it might rev a tiny bit but wont go. ive played with the idle screw and it basiclly makes no diff. from what ive read on it i think it has to do with the exhaust or the carb but im not sure. any suggestions? thanks