What tool should be used to verify the ignition system is functioning correctly?

Using a spark tester is essential for verifying that the ignition system is functioning correctly. This tool specifically checks the presence and quality of the spark produced by the ignition system, ensuring that it is strong enough to ignite the air-fuel mixture in the engine cylinders. A spark tester detects both spark intensity and the correct timing, thus providing a direct assessment of the ignition system's performance.

In contrast, while a multimeter can be useful for testing components of the ignition system such as coils or wiring, it does not directly evaluate spark output. A compression gauge measures the engine's cylinder pressure, which is important for overall engine performance but does not assess the ignition system specifically. A timing light, although beneficial for checking the timing of the ignition system regarding how and when the spark occurs in relation to piston position, does not provide information regarding the actual functioning spark. Therefore, the spark tester is the most appropriate tool for directly assessing ignition system functionality.