bb, Your best bet on making that motor hum is to get a big bore carb. Trust me when I say that the one that came with it isn't one. You dont need to spend a lot on a carb. The one Pete sells is $18 with shipping! Cheap price for 2000rpm isn't it? High octain gas or low grade wont make any difference in the motor. How fresh the fuel is might. I've bought some gas around here that was just awful smelling because of age. Piper