Hi everyone - I just picked up a little 50cc for my kids to ride in the yard. Its in great shape almost brand new - bought it used.

The bike starts well w/ choke when cold and w/out choke when warm. When up to normal operating temp it idles very high (choke is off) almost to the point that it takes off - after idling for a little while the idle will drop down to a more normal idle range, then slowly increase back up to that high idle where the bike almost starts to move.

I dont have any rpm meter but the change is drastic. I ruled out a cable issue b/c the bike is just sitting there - the cable is not moving or being pulled on and the rpms go up and down.

I pulled the carb and cleaned it out completely, removed the jets and blew everything out etc. Right now the air/fuel mix screw is about 1/8 to 1/4 turn out (which doesnt seem right) - what could be the issue - or do i need a new carb? Help please!! Thanks!