provide sealing of the fuel metering valves the fuel metering valve retainers 2 guide the fuel metering valves and provide a stop to keep said fuel metering valves from making contact with the solenoid cores it is necessary to prevent said fuel metering valves from making contact with said solenoid cores to prevent sticking due to residual magnetism and to provide a space between the solenoid cores and the fuel metering valves where pressurized fuel may remain to effect the closing of the fuel metering valves the compressed fuel air mixture in the cylinder is fired by the spark plug as the piston nears the top dead center position in traveling upward crank inertia carries the piston past said top dead center position whereupon the piston is forced downward in the power stroke by pressure from the expanding gasses as the piston nears a position in traveling downward that is 3 4 of the way from top dead center to bottom dead center it effects the opening of the exhaust ports to initiate the escape of said expanding gasses as the piston reaches the bottom dead center position of its travel with the exhaust ports now fully open the intake valve train effects the opening of the intake valves to admit pressurized air from the compressor into the cylinder for the purpose of purging the remainder of the spent gasses out through the exhaust ports crankshaft inertia carries the piston through the bottom dead center position to begin an upward movement the purge of spent gasses by the pressurized air continues until the piston in traveling upward effects the.