I would also like to add that I went through all the usual items when checking the engine out. I checked the check valve, tappet clearence is at .003, Diaphram is good with not stretching or holes. Put in new plunger assembly and new spring. The original plunger assembly had a raised notch in the middle of the disk that was sharp. The new one is perfectly smooth, so was the original assembly defective? I also check to see if there was any debris in the regulator housing plugging the holes and check the fuel filter for blockage.