However, the slight introduction of a voltage is a theoretical safety issue as the voltage from a battery-operated continuity light or a multimeter can charge the electrical circuit and potentially enable it to discharge a spark. If used on a magneto, the circuit is open when the contact points are closed, and the circuit is open when the contact points are open. If the circuit is open, there will be no continuity and if the circuit is closed or complete, then there is continuity. The principle of operation for a continuity tester is to introduce a voltage signal to a circuit. Of course, this tool has other names, ranging Buzz Box as a nod to the buzzing or whistling sound that backs up the on and off illumination of the timing lights, to other, very salty terms when struggling with the tool on a late Friday afternoon.įrom the theory of operation standpoint, the magneto timing tool is not a continuity tester, at least in the conventional sense of how a continuity tester works. This discussion will take a closer look at how the magneto timing light tool can contribute to false diagnosis of a magneto problem.įor the purposes of this topic, the Magneto Timing Synchronizer will be referred to as a Magneto Timing Tool. The typical action is to send the magneto back to Kelly for warranty inspection, only to be informed that the magneto contact points operated perfectly normally when checked on the bench. Connect a lead to the magneto ground point, connect a lead to the p-lead terminal, and as the magneto rotor shaft is turned, a light on the front of the tool will turn on and off as the contact points open and close.Īll too frequently, however, a mechanic will struggle with timing a magneto, unable to get the tool to indicate that the contact points of one or both of the magnetos are opening.

The difficulty of using this tool can be baffling as the theory of operation is as simple as it gets. Despite its simplicity, the magneto timing synchronizer, commonly referred to as the magneto timing tool, can be one of the most frustrating tools for even the most experienced mechanic to use.

Timing a slick magneto