<VV> The End-All to the Accelerator Pump Question

[Grant Young]

Okay, here's the real answer to the secondary accelerator pump question. 1. If the carburetor has a circuit from the pump to the needle cavity, the needle cavity will have a single squirter hole and the carb should have a pump cup. 2. If the carburetor does not have a circuit from the pump cavity to the needle cavity, it will not have a squirter hole and should not have a pump cup. I have found the second type of carb only on secondaries claimed to be from original 140HP A.I.R. engines. If there is a rivet in the bowl at the bottom of the pump cavity, it has a circuit. If there is not a rivet at the bottom of the pump cavity it might or might not have a circuit, so you have to check.

The same applies to A.I.R. primary carbs. If there is a rivet on the side of the bowl where the enrichment circuit should be drilled, it will have one. If not, it won't. And if your secondary carb has a hole in the bottom of throttle body, where one would normally be, it is one of those very rare secondaries with an (non-adjustable) idle circuit. It will not work, of course, if the venturi cluster has been swapped with one from a standard secondary carb. Probably more than you wanted to know, but this is, however, the last word on it :-).
The Carbmeister