400ex idle adjustment screw help

[drag93ex]

i just bought an 02 400ex. problem with it is that when you start it up you have to throttle it. once the motor gets warm, it seems to idle slightly better but still dies out. i have tried to adjust the idle screw (the one with the straight screwdriver head), problem is that the screw turns the way i want, but goes back to where it was. kind of strange to me so i need help. why does the screw turn itself back?

[GPracer2500]

Open the throttle a little when your adjusting. That keeps pressure off the screw which helps. Could be the screw is frozen. Follow it over to the other side of the carb and make sure it's actually turning on the other end. If you take off the that black plastic cover you can see what turning that screw actually does.

[drag93ex]

i will take the black plastic cover off later on and see if it is turning. and get back on here and post.