Try cleaning the carburetor, there could be some gunk trapped in there causing the fuel not to spray properly, or you may find out that the carburetor isn't spraying enough fuel in there to began with. Also see if the choke is working properly, no choke or poorly functioning choke will cause you to have to pump the gas a lot on cold starts. I know this from experience from before I had the electric choke installed on my Chrysler, before when I had no choke installed at all, I had to pump the hell out of the gas on cold starts.

I'm familiar with that setup since I've owned 1980s AMC vehicles with the same engine. It features an electronic feedback carb that fine-tunes mixture in real time combined with an ignition system that can vary ignition timing of individual cylinders on the fly, all computer controlled. As I recall there is also an electric heater in the aluminum intake manifold to aid fuel vaporization when cold. All this stuff actually works quite well when everything is in good shape and adjusted properly. 

For your immediate problem the choke is the primary suspect. When you pump the gas multiple times the accelerator pump is squirting gasoline into the intake and enriching the mixture. That's the choke's job.