Add some Sea Foam to your gas per the instructions on the can. Do not change your fuel-oil ratio; just add it in addition. It is real good at cleaning up carbon and things in general in the fuel and the combustion process. I keep it in my fuel and I can wipe my finger on the inside of my propeller and have very little residue to look at. Pop a plug and look at a piston crown and clean as a whistle.
Mark
