What would cause this surging?

I was doing a little tweaking to my carb and this intermittent surge appeared. Basically i would crack the throttle(in park) and the engine would have an rpm surge that would go from say (1500-2k)-0-(1500-2k)-0 even after i had let off the throttle. Another crack and it'd go back to normal. The first time it did it, i shut the car off immediately and it puked fuel up out of the carb.

Adjustments: set the floats per the manual, adjusted my idle mixture to read in the 12-13:1 range.
Author: admin