What was found
PILOT EXPERIENCED FUEL INTERRUPTION TO ENGINE WHILE ENROUTE. SWITCHED FUEL TANKS AND ENGINE QUIT. MADE EMERGENCY LANDING. NO INJURIES OR DAMAGE TO AIRCRAFT. REMOVED AC FROM FIELD TO LOCAL AIRPORT (N75). DRAINED ALL FUEL FROM WING TANKS. FOUND WHILE DRAINING FUEL WITH FUEL CAPS ON THAT DRAINING FUEL WAS SLOW. REMOVING FUEL CAP QUICKENED FLOW RATE AT FUEL DRAIN. AFTER CLOSE INSP FOUND VENT HOLES CLOGGED WITH MUD. FOUND VENT TUBE IN LT WING WAS RESTRICTED. BLOWING NITROGEN THROUGH TUBE FREED UP BLOCKAGE. FRESH FUEL WAS INSTALLED IN EACH TANK AND FUEL CAPS WERE REPLACED WITH NEW UNITS. A FLIGHT WAS MADE WITHOUT INCIDENT. AFTER ARRIVING, THE OWNER REQUEST WE REPLACE THE FUEL SELECTOR AS A PRECAUTIONARY MEASURE.