[AZKen]

Even though you "siphoned" it seems it still took a long time. Several 15 second intervals is a long crank. Anyway, about the choke. We are talking about new fuel pumps and possibly no gas in hose or carb. The motor cranks with the starter. The pump is pumping slower than even at idle. So when gas does finally get into the carb/manifold/combustion chamber, you want a good rich load so motor starts as fast as possible to begin pumping faster. So having the choke closed gives you that rich shot. Then you gradually open it, as you know, as motor stabilizes. Having it closed has nothing to do with more pump suction per se. It is just part of a dry start procedure that I thought we were all discussing.

Yes the choke has an impact on gas. Air is part of the gas mixture.

Running out of gas may take the same procedure.

Some say they prime, some say they don't. No argument. What works is good.