Abstract: A pumping unit for actuating a down hole pump is disclosed for a pumping units of the type wherein a counterweight is mounted on a beam to balance a down hole load consisting substantially of pump rods. One end of the beam includes a static counterweight to balance the other end of the beam about a center pivot point, the other end of the beam including a horsehead connected to the pump rods. A prime mover is mounted on the beam for rotating beam mounted cranks including at a terminal end thereof dynamic counterweights which move in a rotational cycle in conjunction with a pumping cycle of the pumping unit. The dynamic counterweights, at a maximum lever arm from the center pivot point of the beam, counterbalance the fluid being pumped during the work stroke of the pumping unit. As the dynamic counterweight rotates it passes through a minimum lever arm from the center point corresponding to a minimum down hole load.