I took off the top half of the carb to check out the float. The needle was stuck and wouldn't budge. I soaked it in carb cleaner for a few hours, put a fresh fuel filter in (the rebuilder had put the old dirty one back in) and the needle came loose.
The float was about an 1/8" too low according to the 1962 edition I have of Motors Auto Repair Manual, so I raised the float level to the 1 19/32" speced in the manual and a 1 3/4" float drop. There is no fuel inside the float. The float/fuel filter seem to be working fine now. The bowl fills up, the accelerator pump squirts.
But the engine still isn't getting any gas at all. It was running when the carb was taken off for the rebuild. And when you pour a little gas down the carb, it starts right up and runs until the fumes are used up, then it dies. What's wrong with this stupid carb? I thought maybe the main jet passage was plugged. But I took a turkey baster hand pump, put a little gas in it, placed it tight up against the main discharge vent that goes over the center of the venturi. When you squirt it, a 3 foot stream of gas shoots out of the jet - that's all free and clear. It's got gas to the bowl, the jet can pick it up and feed it to the engine, but it apparently doesn't. HELP.