Sounds like it is geting flooded. it could be that you are over priming it... If your idle is too high, you would notice it when the truck is running. perhaps your LSN is very rich?
Make sure to use a hot plug in these engines, an OS #8 or similar. Also, double check that your glow ignitor is working good and fully charged. i have ran both the NT 16 and NT18, and havent had any starting trouble with either of them.
Also, i actually prefer pull starts, just less equipment to lug around and they always work good for me.