one more carb question

[NeCrOmAnCeR]

I'm guessing you are talking about the adjustment bolt on the end of the pump arm. It is used to set the maximum pump shot. You can increase or decrease the volume of the shot by adjusting the screw. To truely adjust the pump you must replace or flip the pump discharge cam, which is a small plastic piece on the throttle shaft. A lever from the pump linkage rides on this cam. You can also replace the discharge nozzle assembly to increase the orfice (sp?) size. Do a search on the web for tuning instructions and you should find all the explanations you need. Good luck.