My first tank of gas was 87 octane with synthetic 2 cycle, but I ran out of sythetic oil and put in some of my weed whacker's pre mixed gas/oil which uses regular 2 cycle oil. The weed wacker mix seemed to give off a lot more white smoke than the other two tanks using synthetic. Of course the weed wacker mix has probably been in my garage for 2 years or so, which could be problematic by itself. Does anyone else notice a difference?