[carbking]

The bodies with the check valve design will function best with leather accelerator pumps. The cheaper neopreme pumps, especially those without an expander spring on the skirt, tend to flex when lifted, not allowing a full charge to be pulled into the pump well from the bowl.

As others have mentioned, the squirter size effects the timing of the pump shot, not the volume.

Also as others have mentioned, the height of the pump (changing the volume of the pump chamber below the pump) effects the volume of the pump stroke.

Different length pumps (pay attention to both the "free" length and the compressed length, not all articulations are the same dimension) can be used to effect the chamber volume. This volume may also be adjusted by bending the pump activation rod (from the throttle arm to the intermediate pump shaft) without changing pumps.

The check ball design tends to be much more reliable than the slotted design. The slotted design depends on the pump skirt flex to charge the pump chamber. If the rubber (or whatever the current buzzword is for rubber) skirt hardens due to the use of ethanol-laced fuels, then the flex is insufficient to fill the pump chamber, and the pump shot is adversely effected.

Jon.