Home › Forum › Ask A Member › This Test: You think it shows an incorrect Spark Plug….or just a bad one? › Re: This Test: You think it shows an incorrect Spark Plug….or just a bad one?
Jeff, one of the ways to tell which spark plug on a multi cylinder 2-stroke is not firing is to use an auxiliary gap or simply pull the plug wire a short distance from the spark plug while running. This creates a higher " resistance " and makes the ignition system work harder. If it will jump the auxiliary gap at the higher voltage requirement then it will easily jump the gap at the plug tip and fire that cylinder if the plug is not internally shorted. Not only will it fire the cylinder but the spark itself will be a "fatter" spark due to the fact that the KV of the spark is higher (due to the auxiliary gap) than what is required to simply jump the plug gap. Kinda’ the same theory as a resistor plug.