Manually operated means used in connections with sparking devices for determining the time in the cycle of operation of the engine at which the charge will be ignited, in combination with means for acting upon the exhaust-valve of the engine to regulate the said valve, said last-mentioned means ordinarily operating either to cause the exhaust-valve to be opened upon the compression-stroke of the engine to thereby facilitate the starting thereof or to maintain the exhaust-valve in a partially or wholly open position thereby acting as a manually controlled speed-regulator.
