The pilot's failure to maintain minimum control airspeed which resulted in the loss of control. Factors were the bent collar of the left main fuel tank refueling neck which resulted in fuel siphoning from the tank in flight, the pilot's failure to follow procedures to cross feed fuel from the right main tank to the left engine which led to left engine power loss by fuel starvation, the pilot's lack of total experience in the make and model of airplane, and the dark night light condition.