I have been premixing my gas for a while now. the other day i filled up without a premix and it drove fine for a little while. I started to notice a loud raspy intake sound whenever i accellerate and it idled like crap. Really rough. so out of couriosity... i through some 2 cycle oil in my gas and it all went away and started running smooth again. Anyone heard of this problem? would it not be a sufficient oil supply from the oil supply nozzles?