According to the pilot, the airplane was out of annual inspection and had been in storage with the wings removed for an unknown time period. He reassembled the airplane and applied for a ferry permit to relocate the airplane to a location where further maintenance was to be conducted. A ferry permit was issued. The pilot fueled the airplane with 35 gallons in the left wing and no fuel in the right wing. During the takeoff initial climb, the engine lost power. The pilot switched the fuel boost pump to the high position and the engine ran momentarily and lost power again. The pilot executed a forced landing and the airplane collided with trees and came to rest in a pond. An FAA inspector examined the airplane after it was recovered from the pond, but was unable to determine the reason for the loss of engine power.