Classic/Antique Car Repair: 1972 Buick Skylark GS Hard to Start, 1972 buick skylark, buick skylark

Question
I have a '72 Buick Skylark GS that is hard to start if it has been sitting for a few days without running. I have to pump the accelerator continually while cranking over until it starts then gently keep pumping it until it continues on its own.  When hot restarts OK. Carb is a Rochester Quadra Jet.
I changed all the rubber fuel lines, fuel pump, tuned up to OEM specs replacing plugs, points, condenser, replaced ignition coil with new one, had carburetor rebuilt by professional carb shop. Also, checked to see if it was leaking down at the epoxy seals on the bottom of carb and it appears tight and dry.
Help!
Thank you.

Answer
Have you checked to be sure that the automatic choke is closing as tight as it should? The springs in the choke will loose their strength after a while and that could be the problem. To check for float bowl leak down I usually take the carburetor  off the car and strip it down. I then place the float bowl, the center section of the carburetor, on top of an empty large plastic coffee container minus the top. Then fill the float bowl with gasoline and let this set over night. I usually do this in the car port as there is plenty of ventilation. Then check after 24 hours to see if any gasoline has leaked out. Let me know what you find doing this check.