An Aeronca 7AC pilot suffered an engine failure and landed in a field. Added fuel; drained the sumps; took off and flew to a nearby airport where he filled the tank; then flew the aircraft back to its home airport.

Narrative

I was flying an Aeronca Champ 7AC. About 15 minutes into the flight the engine RPM dropped. I applied full Carburetor heat and full rich mixture. Engine briefly responded then 30 seconds later it quit. I was at 1200 feet and 4.2 miles East of the airport. I knew I would not make the airport so I set up a landing in a farm field below. I trimmed the plane for best glide speed and made the approach. Before landing I called mayday to alert authorities of my situation. Plane and pilot were undamaged and uninjured in landing. I alerted authorities via radio and later cell phone that neither I or the plane were damaged. Before leaving on the flight I did a complete preflight check. I inspected the control surfaces; checked the fuel gauge it read 1/4 of a tank. I visually checked tank for gasoline. No water or other contaminants appeared when sumps were checked. During run-up before takeoff no issues appeared. Both Mags were fine as was carb heat. Suspecting water in the gas or some sort of contamination; purchased aviation fuel at ZZZ and took it to the airplane. I put the fuel in; checked the sumps and found no contamination. I started the plane;and did a run-up. I shut the engine down; checked for leaks; or other issues. I restarted the engine and did a high power run-up. Holding full power for over 2 minutes; no issues appeared. The engine ran perfectly. I deemed it safe to fly so I took off and flew to the originally planned destination. I purchased more fuel and drained the sumps. I then ran the engine for over 10 minutes at a high power setting. The engine ran smoothly and reliably. I flew the plane to its home base and landed. My Mechanic is inspecting the aircraft to determine what caused the engine to lose power. In hindsight; I could have done a dipstick check of the tanks;that would have given me a better indication of exactly how much fuel I had. Additionally; the aircraft had not been flown in over a month before the engine out landing. The plane was put in the hangar with low fuel levels. December was a wet and cold month. Condensation in the tanks could have formed during that long period of inactivity causing or contributing to the loss of power.