What was found
PILOT EXPERIENCED FUEL INTERUPTION. MADE EMERGENCY LANDING IN SOYBEAN FIELD. NO INJURIES OR DAMAGE TO AC. REMOVED AC FROM FIELD TO LOCAL AIRPORT. DRAINED ALL FUEL FROM WING TANKS. FOUND WHILE DRAINING FUEL WITH FUEL CAPS ON THAT DRAINING FUEL WAS SLOW. REMOVED FUEL CAP, QUICKENED FLOW RATE AT FUEL DRAIN. AFTER CLOSE INSP, FOUND VENT HOLES CLOGGED WITH HARD MUD TYPE SUBSTANCE. ALSO FOUND THE VENT TUBE IN THE LT WING WAS RESTRICTED. BLOWING NITROGEN THROUGH TUBE FREED BLOCKAGE. FRESH FUEL WAS INSTALLED, FUEL CAPS WERE REPLACED WITH NEW. LENGHTY RUNUP WAS PERFORMED WITH NO DEFECTS NOTED. FLIGHT WAS MADE WITHOUT INCIDENT. AFTER ARRIVING, OWNER REQUESTED TO REPLACE THE FUEL SELECTOR AS PRECAUTIONARY MEASURE.