What was found
THE FUEL FILTER GASKETS SWELLED CAUSING THE FUEL FILTERS TO LEAK A LARGE AMOUNT OF FUEL OVERBOARD WHILE IN FLIGHT. THE PILOT WAS UNAWARE OF THE LOSS OF FUEL UNTIL AFTER HE LANDED. APPARENTLY GASKETS ARE NOT COMPATIBLE WITH CURRENT BLENDS OF 100LL. WAS TOLD BY RAYTHEON TECHS THAT LOCAL AVGAS MAY HAVE LARGER AMOUNTS OF BENZENE AND TOULENE AND MAY BE CAUSING THE SWELLING OF THE GASKETS. THIS PROBLEM HAS OCCURRED MULTIPLE TIMES. PROBLEM UNRESOLVED AT THIS TIME.