All Moki radials use Walbro carbs. The APS Power Fuel pump is simply hooked to the Walbro carb. The carb will accept the fuel just fine. The pump flappers will let the fuel flow through to the diaphragm. Yes the stock carb would need to be leaned for gas use. The needle will become much more sensitive! Gas conversions for these engines is appropriate to this thread as long as Evolution engines is the subject. I have concern for gas conversion with a plain main bearing. The Saito radials on gas have been seizing. There is a gentleman that has been machining the master rod in these engines and presses in a phosphor bronze plain bearing. -Tom