Roy, we're up against an age-old problem in describing what's going on. The way I taught 30-something years' worth of students was this:
"Cranking" is the act of the starter turning the engine over. It's either slow, normal, too fast, or not at all.
"Starting" is when the engine actually begins to run under its own power. Far too many people blur the distinction between cranking and starting because they've never been taught the difference, A "slow crank" or "no crank" situation needs a completely different diagnostic procedure than a "cranks but doesn't start" condition.
What the original symptom being described seems to be is a "cranks normal speed but won't start" situation, caused by a temporary flooding condition from overheated fuel in the float chamber. At least that's what I understand from the description we've been given. Holding the throttle wide open during cranking does two things- - - -it provides plenty of air to dilute the flooded mixture in the intake, and it avoids adding more gasoline to the mix by pumping the gas pedal and making the accelerator pump put more gas into the manifold.
Jerry
