Carb idle question

[psg]

I have been trying to set the idle on my '78 stock carb. I got the timing right and the idle was at about 1500 rpm after the rad fan came on a couple of times. Backed off the idle screw connected to the accelerator linkage to almost the last thread . The idle would not drop. I can raise the idle but not reduce it. So I went to the cold idle screw on the bottom of the carb and lowered the idle there. I don't think this is right,,,, is it? psg

[So Cal Mark]

the fast idle adjustment should only come into play if the choke is partially closed. Once the choke is open the fast idle adjustment shouldn't set base idle