I believe there is some misinformation on the Perry Pump, and Perry Pump Carburetors. The original Perry Pump is an oscillator pump. It works on vibration. There is also a Perry Pump that replaces the engine rear cover, and that pump works on regulated crankcase pressure. The pump carburetors have a larger bore, so that more fuel, and air can be ingested. For a given engine, the pump carburetor wouldn't work on suction. Not only would the mid-range be a miss-match, but there would be insufficient fuel draw at wide open. Greg