Abstract: A low-polluting lawn mower includes a frame having ground-engaging wheels, a seat for a driver and a steering mechanism to permit the driver to control the direction of movement of the lawn mower on the frame, a four-cycle engine mounted on the frame and having a drive shaft operatively engaged with one of the wheels so that the engine propels the lawn mower, a propane gas supply on the frame including a tank containing liquified propane gas, a fuel connection from said propane gas supply to the engine including a carburetor having a venturi and equipped with a spud to feed propane to the venturi and a fuel control assembly including a regulator and a fuel lockoff, and a blade operatively engaged with the drive shaft so as to be driven for cutting grass when the engine is fueled by propane from the supply.