What was found
FUEL STRAINER WOULD NOT DRAIN WHEN ACTUATED. INVESTIGATION REVEALED THAT THE RUBBER NIPPLE HAD SEPARATED FROM THE PLUNGER, (P/N 0756010-11). THE FUEL SUMP DRAIN ON THE LT WING ALSO LEAKED AND WAS REPLACED. THE AC HAD RECENTLY BEEN PURCHASED AND IT WAS NOTED THAT AUTO FUEL HAD BEEN USED IN THE PAST. AN STC WAS SECURED AND INSTALL IT ON THE AIRCRAFT. IT IS MY OPINION THAT AN AUTO FUEL WITH ETHANOL ALCOHOL HAD BEEN USED, IN THAT THE PLUNGER NIPPLE WAS (ROCK) HARD AS WAS THE FUEL SUMP DRAIN SEAL. ALL MECHANICS NEED TO MAKE NOTE AS THIS COULD HAVE CAUSED ALL THE FUEL TO LEAK OUT IN FLIGHT AND CAUSED AN OFF FIELD LANDING OR WORSE. IF YOU SMELL AUTO FUEL GO AS DEEP AS NECESSARY TO DETERMINE THE SERVICEABILITY OF THE S