The pilot said that he was asked by one of the owners to ferry the aircraft. When he arrived to get it, he found that the right engine had been shut down during the previous flight. He said that he found the right fuel tank empty and about 20 gallons of fuel in the left tank. The pilot said he loaded 50 gallons of fuel in each tank, after determining that the flight would require only 50 gallons. While descending into Lake Elsinore, one engine quit followed quickly by the second one, and the pilot landed in a field. FAA inspectors found the right fuel tank contained no fuel and the left tank contained about 50 gallons. No other mechanical malfunctions or failures were identified during the investigation. One owner of the aircraft who was repossessing it from a partner said that after the accident he was informed that due to a pump failure, the other owner had 'somehow rigged the aircraft so that both engines would be supplied by the right fuel tank.' The owner said that both he and the pilot were unaware of this modification.