Without the oil to keep the fuel from burning at a high temperature, the piston will seize up. The metal on the cylinder and the piston will heat and expand to the point where the piston no longer fluidly moves up and down inside the cylinder. This will cause friction inside the cylinder, eventually causing the piston to freeze up or stop moving completely. This will also cause the crankcase to stop turning underneath the piston. When the crankcase stops moving, all other systems shut down instantly. http://www.zjhuaruitools.com/gasoline-chain-saw/