Originally Posted By FreeFloater:
Start researching tcw3. It's used in marine 2 stroke engines, and does a great job in regular car engines a well (in much lower doses)
You can buy a gallon of tcw3 oil for less than $15 and that should lady you a long time.
I get about 2500 miles out of a quart in my car.
I am not sure what it will do to the ethanol, but it will help lubricate and clean the fuel system. The fact that it's a marine oil probably says something to it's anti corrosion abilities.
TCW3 is simply two cycle oil designed to work in water cooled engines, I would not recommend it in an air cooled app.
Again OP I would try a higher octane gas if you have knocking. You might consider some fuel additive like techron(sp?) to help clean the combustion chamber.