Abstract: A power system comprising a cylinder assembly and a power providing system. The cylinder assembly comprises a cylinder, a piston, a connecting rod and a crankshaft. The cylinder is pivotally coupled to a frame and includes opposing end walls. The piston is slidably positionable in the cylinder between the opposing end walls. The connecting rod is coupled to the piston. The crankshaft is rotatably coupled with the connecting rod. The power providing system comprises a vacuum providing assembly, a manifold, a valve actuator arm and a cam. The manifold is coupled to the vacuum providing assembly and with the cylinder selectively between the piston and a first opposing end wall and between the piston and the second opposing end wall. The cam is coupled to the crankshaft and the valve actuator arm.