i recently purchased a kfx 400 that sat outside last winter at the police impound so when i started it gas would pour out the overflow so i took off the carb and my friend cleaned it for me and when i put it back on the gas problem was fixed but my idle is like really high, like 4000 rpms and i tried to adjust it at the idle control screw but it won't get any lower. anyone have any ideas

 

This can only be a couple of causes, i would check the choke line to make sure its not getting stuck or anything, check thumb throttle to make sure that it is retracting al the way back when you if give it gas or check to see if there is play in your throttle line. Check the part where the throttle cable attaches to the carb.
Did your friend remove the carb when he cleaned it?? Also how much did you pick the quad up for?

 

i got the quad for 2500, its what my friend had left in payments. i took the carb off myself and reinstalled it. as for the throttle part, i checked to make sure it was going all the way back. the choke was filthy when i unsrewed it so it could be stuck, im gonna check that later but would that make it idle that high?