ATV Wont Stay Idling?

[bulletproofcracka]

Well i have been helping my uncle fixing a motor on a old 3 wheeler that hasent ran in 10 years due to the piston rings being bad and a couple gaskets. anyway its all back together now with new parts and the timing is all most dead on and i just cleaned the carb and it will start and stall if you do not hold the gas full throttle. before i cleaned the carb it wouldn't even start so im making a little progression. and i did try to adjust the pilot screw and idle and it did nothing. also the plugs are turning pretty black after just being on for a few mins. it is a 1984 YTM200L TRI-MOTO. if you need more info ask. thanks in advance.