Abstract: An improved system to control the flame, efficiency and flow rate in a waste oil feed system and burner. The system controller comprises a positive displacement waste oil pump, a variable speed motor connected to and driving said pump, and a motor speed control which control the speed of the motor, the speed of the pump and, consequently, the flow rate of the waste oil. Controlling the flow rate of the waste oil precisely allows the more efficient atomization and combustion of waste oils with different combustion and flow properties.