THE PILOT REPORTED THE AIRPLANE WAS REFUELED TO CAPACITY OF 50 GALLONS BEFORE DEPARTURE. HE STATED HE WAS 4.2 HOURS INTO THE FLIGHT, DESCENDING FROM 8000 TO 4000 FEET MSL, WHEN THE ENGINE SPUTTERED SEVERAL TIMES, THEN LOST POWER. ACCORDING TO THE PILOT, THE LEFT AND RIGHT FUEL GAGES INDICATED 4 AND ABOUT 7 TO 8 GALLONS, RESPECTIVELY, WHEN THE POWER LOSS OCCURRED, AND THE FUEL SELECTOR WAS SET TO THE LEFT TANK. ATTEMPTS TO RESTORE POWER, INCLUDING SWITCHING FUEL TANKS, WERE UNSUCCESSFUL. THE INVESTIGATION DID NOT DISCLOSE EVIDENCE OF MECHANICAL MALFUNCTION. THE EXAMINATION REVEALED THE CARBURETOR INLET FUEL LINE WAS EMPTY. THE LEFT WING SEPARATED DURING THE CRASH IMPACT SEQUENCE, CAME TO REST IN A TREE, AND WAS NOT ACCESSIBLE FOR EXAMINATION. THE AMOUNT OF FUEL IN THE RIGHT TANK WAS UNDETERMINED. PERFORMANCE CHARTS INDICATED THAT WITH THE PILOT'S REPORTED POWER SETTINGS, THE FUEL FLOW SHOULD HAVE BEEN ABOUT 8.4 GALLONS PER HOUR.