When the pilot neared the destination airport, he was unable to locate it. Subsequently, the engine lost power. He made a forced landing in a field; the landing gear collapsed during the landing. The accident occurred about 5 miles east of the destination airport. The flight duration was about 3.5 hours. The pilot used the Hobbs meter to track time. The investigation revealed the Hobbs meter was operating about 60% slower than the actual elapsed time. The pilot reported he switched fuel tanks, from right to left, 1.1 hours of Hobbs time (estimated 0.67 hour actual) into the flight. The examination revealed virtually no fuel in the fuel lines forward of the firewall. About two ounces of fuel was drained from the carburetor. The fuel selector was positioned to the left tank. There was no fuel found in the left tank; however, the fuel lines from the tank were severed. Eighteen gallons of fuel was drained from the right tank. The engine operated satisfactorily during a test run.