Pumping the gas is not particularly helpful, even for cold starting. If you've got an automatic choke, pushing the pedal down once, gently, will allow the choke plate to close and the fast idle cam to index. Half of the throttle travel or less is plenty. Then just crank the engine until it fires, and let the fast idle take over.
For manual chokes, it's even simpler. Pull the choke knob out all the way, crank, and push the knob in partway once the engine fires to prevent flooding and stalling. A few cold starts will educate you on how much relief from full choke you need to get a smooth warmup.
Jerry
