With throttle valve wide open, the top of the pump lifter arm should be parallel to the top surface of the bowl cover. Bend lifter arm to adjust.
If your pump looks like this, you need rebuild kit PK6125
If your pump looks like this, you need rebuild kit K7002
When prepping your carburetor for a rebuild, make sure you polish the pump bore carefully with Crocus Cloth. You want to remove any burrs or scratches in the surface of the pump bore walls, otherwise you'll end up with wear spots on the accelerator pump which will siginificantly shorten it's life.
