At about 10:00, EST, a Cessna 150 suffered substantial damage during a forced landing. The pilot was not injured. The pilot completed three touch and goes before departing the traffic pattern. While climbing through 900 feet msl, the engine started running rough. The pilot applied carburetor heat but the problem persisted. Unable to maintain altitude, the pilot selected a field for a forced landing and then the engine failed completely. The airplane touched down smoothly, but encountered rising terrain and the nose gear collapsed. Investigators found that the fuel tank vents were blocked by mud deposited by insects and the carburetor bowl was empty. The inspector removed the filler caps from both fuel tanks and the carburetor bowl filled with fuel. With the engine still attached to the airframe, the engine ran normally.