Spark In-Line Checker

An in-line ignition spark tester is the quickest way to determine if a lack of spark is the issue if your engine won't start or is running rough. This device clips into the lead and over the end of the plug. When the motor is cranking over, the ignition spark tester should flash as the spark goes off. If there is no flash, further efforts to solve the problem can be directed at the ignition system or the spark plug and leads.