Starting line hesitation

[Mike Taylor 3601]

I would say your gasket is bad like Joe said, or needle and seat is leaking. My car has done that before,finally figured out it was needle and seat, I have them leak,but they don't pour fuel out of it,they will leak slightly,car will idle about 200-300 rpm slower,and bogs a few feet out.
The best test I have come up with is remove top and hold float pivot rod with your finger so float works like the top is on carb,then have someone turn on fuel pump, after needle and seat closes watch fuel level in bowl for 1-2 minutes,it should not creep any higher up at all,it may take a minute and if leaking will rise very slowly, be careful sometimes when first turn on pump it will spray fuel out,I usually use my other hand as a shield over carb,till it calms down.
The best thing I have found to prevent this problem is to run carb dry and pump fuel out of tank when I get down racing and store the car,even for one week.
Mark,
I still use the tape trick, I use 3M super33 tape is a soft and flexible electrical tape.

Mike Taylor 3601