when i first start my car it idles at 2000 when i try to turn the curb idle screw to set idle it wont go down past 1500. Does the choke have to be fully open to set idle?

 

There is a high idle cam tied to the choke (you can see a green weight on the passenger side of the carb - that's the other end of the high idle cam), and the normal curb idle adjustment. Sounds like you're trying to adjust the curb idle while the high idle cam is still engaged.

When the choke is fully opened and the throttle brought off-idle, the green weight drops down, disengaging the high idle cam.

 

ok thanks im new to carbs but i have a basic understand i just tend to play with things before reading up on them