The next time you have a "hot no-start" condition, do these things.
First, look down the carb throat with the throttle held all the way open (engine not running, of course) and see if you have fuel pooled or pooling on the intake runner. I would do this as soon as you shut the truck off after an operating temperature drive. Then look again when you come back from buying celery.
If you see fuel or dribbling, your accelerator pump is most likely leaking.
If there is no fuel leaking or dribbling, look down the carb throat and goose the throttle manually. If you don't see a strong squirt of fuel, your accelerator pump isn't working.
