Accelerator pump

Nov 3, 1999
Can anyone explain the exact purpose of the Accelerator Pump? My 99 looks completely different than my friend's 2001. The older carb actuates the push rod at low throttle, but the new one seems to do it the other way around. But since we were working on the new one, I figured I would verify it here.

Thanks for your help.
Apr 28, 2001
Accelerator pump!

The accelerator pump is there to squirt raw fuel into the cylinder when you open the throtle to compensate for the sudden leanness when you do open the throtle. the other type of fourstroke carb is a cv carb, where when u open the throtle it ativates a butterfly to let in fuel and when pressure builds up the slide open the let in more air. The pumper carb gives quicker throtle responce.