My truck always requires 2 pumps before it wants to start, just something I figured was normal on these trucks and carbureted engines in general. If it doesn't seem like there is enough juice getting to the starter from the battery, check the positive battery cable and see if it needs tightened down on the starter and if it is in good condition. Honestly I think you will always have to pump the gas atleast once to get it started. I'm not very helpful.
