Drew, the secondary will only open when the primary is basically wide open, and it's vacuum-actuated. The actuation rod for the vacuum is on the front of the carb. You can take a paper clip and put it on that rod. Slide it up against the vacuum chamber, and if after driving around spiritedly you find that the paper clip has been pushed down about an inch then you will know that your secondary is opening.
Last edited by subzali; 10-11-2012 at 12:13 PM.