A capacitor discharge ignition system is provided with a control arrangement to prevent operation of an engine at excessive speeds. For example, when the engine exceeds a predetermined speed of operation, the control arrangement is effective to terminate the generation of the ignition firing pulses to the spark plug of the engine. The control arrangement includes a capacitor connected at one end to the cathode of an SCR switching device that controls the discharge of a charging capacitor into an ignition coil. The other end of the capacitor is connected in the triggering circuit of the SCR. The capacitor discharge ignition system is arranged to charge the charging capacitor during a first half cycle of operation of one polarity and subsequently to discharge the capacitor into the ignition coil by triggering the SCR during the following half cycle of operation of opposite polarity. The charging of the capacitor and the triggering of the SCR are controlled by voltage and current waveforms generated by a control winding that is disposed on a ferromagnetic core. The ferromagnetic core is positioned adjacent the rotating magnetic field that is developed for example by a permanent magnet carried by the flywheel of the engine.