Abstract: A radial motor powered by pressurized gas is disclosed as used for starting the internal combustion engine of a portable implement such as a powered chain saw or lawn mower. The motor is designed for economical manufacture and assembly, durability, and economy of gas used. It includes pistons formed of stiff resilient material that in assembly are snapped onto the outer ends of connecting rods and held in place during operation of the motor without the use of retaining rings, pivot pins or screws. The inner ends of these connecting rods are held in sockets in connecting rod mounting means either by the shapes of the sockets or by the resilience of either or both of the connecting rod and mounting means. The motor includes a rotatable valve driven by a free end of the crankshaft to feed gas to the cylinders.