I filter the fuel before it goes into my gas can, then I have an inline filter inside the can which feeds the fuel to my Holley electric fuel pump. From the pump the fuel travels thru another inline fuel filter (one of those translucent type) to the aircraft tank which has a Du-Bro clunk/filter and straight to the carb. My gas is either Citgo or Exxon 93 octane with Pennzoil air cooled 2stroke oil. I've been running this combo since 1985 and all of my Zenoah's and Fox engine have been running flawlessly. Oh, I only use NGK BPMR7A plugs too. What does all this mean? RELIABILITY.....