55.2-59 Starting issue

[55Trucker]

I took my 55.2 3100 235 out for a 25 mile ride today, now that I've rebuilt the starter, put in a new fuel pump, rebuilt the carb, and put in new fuel lines. It ran great! With one exception: my wife and I made a stop on the way home for an ice cream, which took about 15 minutes. Then I had a dickens of a time getting it restarted, almost like it had no fuel. I had to crank it about 4 times, hitting the gas pedal a couple of times between cranks. It finally started.

Any ideas on what might have cause that? The tank is 3/4 full.

Thanks!