i have a brand new 200cc Chinese atv and i have to adjust the screw every time i ride. it starts out screwed in all the way then gradually unscrew for about a 1/2hr till the idle is normal. iv tried adjusting the choke instead but that didn't help. your thoughts?

 

is the spring tight that holds the screw in place? Might have to stretch the spring a little bit.

Are you sure the choke is operating correctly? Idle should not be adjusted until machine is up to operating temp and choke is off. Manual or electric choke?

 

its a manual choke. i start it with the choke out and carb screw adjusted to high RPM's. butonce it starts i push the choke back in and it wont stay running without throttle 1/2 way.

 

The choke needs to stay on or partially on until machine warms up.

 

Blocked Pilot Jet. Remove the bowl from your carb and clean both main and pilot jet. You should be able to see light thru the holes.