On June 11, 1996, at 1940 central daylight time, a Piper J-3, N35505, operated by a commercial-instrument rated pilot collided with a park bench during a forced landing following a loss of engine power. The pilot and passenger were not injured. The airplane received substantial damage. The local 14 CFR Part 91 flight was operating in visual meteorological conditions without a flight plan. The flight departed from Princeton, Minnesota, at 1930 cdt. The pilot reported that shortly after takeoff, while in cruise flight at 1,000 feet above ground level, a loss of engine power was experienced. He reported that he selected a landing site and attempted to regain power by applying carburetor heat and by moving the throttle. The airplane was landed on a golf course. During the landing the airplane contacted a park bench and the landing gear collapsed. The pilot told an Inspector from the Federal Aviation Administration (FAA) that after the landing he could smell fuel so he shut everything off inside the airplane including the fuel valves. A post accident inspection of the airplane was conducted by inspectors from the Minneapolis, Minnesota, Flight Standards District Office of the FAA. The inspectors reported that compression was noted on all cylinders and the spark plugs produced a spark when the propeller was rotated by hand. They reported the air filter was clean and intact as was the exhaust system. The inspectors reported that the forward fuel tank contained two to three gallons of fuel, the left fuel tank contained approximately four gallons of fuel and the right fuel tank was over flowing. The pilot reported he took off with 20 gallons of fuel on board the airplane. The fuel system consists of three fuel tanks each with a fuel capacity of 12 gallons. The wing tanks are used to feed the forward tank which in turn feeds the engine. The wing tank valves would normally be in the off position unless the forward tank is being fueled from the wing tanks. Fuel system schematics show the usable fuel for each tank as 11 gallons. It also states that fuel should be transferred in level flight and only when the forward tank is less than 1/2 full.