Ignition Spark Tester.

This invaluable tool allows you not only to test if the ignition is sparking but how good (strong) the spark is by measuring the distance the spark is able to jump.

It isn't enough simply to see a spark, for the spark plug to fire correctly and consistently under running conditions the spark needs to be a minimum of around 10,000 volts. This equates to being able to consistently jump a gap of at least 6mm- any less and there is likely to be an ignition problem causing poor running.

• Universal