It sound like a choke issue to me, but wanted to run it buy you guys.
I did mess with the timing the other day, hoping to gain some performance. It's at 35 deg BTDC at about 3000 RPM when the timing stopped advancing. Prior to this, it was less than that, I forgot the degrees. Anyway, before I messed with the timing, it started right up beautifully and choke worked great and would idle a little over 1000 RPM during cold starts.
Now, it has slight trouble, and I mean slight as I can hear the starter having to turn a couple rotations more, to get the engine going. Once it catches, the RPM will slowly dip down, unless I give it some gas and it will keep alive. If I just leave it, it will die. I have to keep my foot on the gas pedal to warm the engine up and maybe after 1 min or so, I can let go of the gas pedal and idle would be fine. This only happens during cold starts.
This is a 350 SBC with Holley Street Avenger electric choke 670. I checked and I get 11.XX volts hooked to the choke that is switched. I tried adjusting the choke and have it turned almost all the way counterclockwise with no difference. I have 15 pounds of vacuum.
Could this be timing related? Or does it sound more like my choke is dead?