PETROL ENGINE, FOUR STROKE (0191) Represents a typical air cooled, side-valve, four stroke petrol engine with the operation of the valves clearly evident. Cam operated inlet and exhaust valves being driven by a gear train from rear of the main crank. As with the two-stroke model, spark plug simulated through a small lamp to indicate the firing point. A pair of 4mm socket terminal for electrical supply. Cross-section of carburetor is shown. Mounted on a stable base. with printed diagram and key. Qty :