a modern gasoline engine contains an electronic ignition system which precisely times the electrical pulse to the spark plug. the advantage of such a device is that it can deliver a full power electrical pulse to the spark plugs even when the alternator is turning very slowly (as in push starting a motor). the outdated method of a mechanically timed ignition system is that is cannot deliver a full electrical pulse at very low engine revolutions per minute (rpm). this may affect the ease of push starting an engine to life.