I threw in some berryman b-12 in my fuel today and ran much smooter...I ran 16:1 for about 2 gallons breakin I imagine may have gummed up the jet a bit? At any rate when I cracked open the top I had a bit of crusted residue in the combustion chamber which is why I put the berryman in. I don't know if berryman increases octane or not but it cleans carbs well and is less than $3 fro 15oz can. That's enough for about 15 or so gallons of fuel!