^ he's right. Cold-start enrichment (choking) only works for small throttle openings. When a throttle is moved open, a carb has an accelerator pump that literally sprays extra fuel into the venturi when the throttle flap(s) open (reason is for what is called "wall-wetting", which is a phenomenon of vapour moving to the outside of the air-stream when the air-stream increases, so the accelerator pump enriches the air-stream during opening of the throttle). But once the throttle is no longer moving, the enrichment spray stops. While cranking, with wide-open throttle, you now have max possible air-flow, but since the engine rpm is low the air-flow is low through the venturi, so the air-fuel ratio (AFR) becomes lean (because the "choking" enrichment can no longer "choke"). As you keep cranking, because the liquid fuel in the manifold and cylinders starts to evaporate, eventually you dry it all out, and reach the point where the AFR is correct for the engine to fire up. At that point, you move the throttle back to nearly closed, so that the AFR remains rich due to cold-start "choking". An EFI system does the same thing as a carb, execpt it sprays into the manifold (there is no ventruri with an EFI system), otherwise the description is the same.
