carb idle

I can't say I have ever had a car do this. I assume a problem in the internal idle.
71 slant points, 2 bbl carter, just stated dong this after 2 years. Starts up, after I have warmed it up ( choke not working), it will try to die, I goose the throttle, it reves up for a second and maintaians that higher idle for a second or so, then it will not keep idling unless I set the idle screw up quite a ways.
I find no vacumm leaks, lash has been set last year, good gas, changed filter. Sprayed carb cleaner down with it running. Cleaned needle and seat. Timing OK.
Any ideas except take apart carb , and clean?