zenith carb help

["B&C Phillips" <bjcap@frontiernet.net>]

Thought I'd post this to the all knowing.
have a 76 TR6 which carbs take a long time to come back down to idle after 
rev ving up.  Pistons are functioning properly, no vac leaks, diaphrams 
correct, and throttle shafts work right. temp boxes new , all adjustments to 
factory spec. These are customer rebuilt carbs. I am not a Zenith kind of 
guy ! Any thoughts would be appreciated.
thanks
Carroll Phillips