I am having trouble starting and I don seem to hear the impulse coupling “click” from the magneto. Any ideas?
First, be sure that your magneto has an impulse coupling. Many engines have the Shower of Sparks system. This is noted by a buzzing sound in the cockpit whenever the starter switch is engaged. Be certain the magneto off and turn the prop through to listen for a click. The absence of the click (or snap) in an impulse coupling requires action as the coupling is probably bad. To check impulse coupling in the field you will need to remove magneto with impulse coupling (usually left magneto). Rotate the aircraft magneto in proper direction by hand and observe that the flyweights in the impulse coupling contact the stop pins. If they do not, then flyweight axles are excessively worn and impulse coupling must be replaced. If flyweights are in good condition, rotate magneto several times to snap the impulse coupling and determine that the impulse spring is not weak or broken.
