Abstract: There is provided a spark plug testing kit for safe and convenient testing of petrol engines. The testing kit has a spark observation device within which a spark gap of a spark plug installed therein may be observed in use. The kit has a positive lead for connection to the engine distributor and an earth lead configured for connection to a spark plug opening engaging device. The spark plug engaging opening device comprises threading for turning into a spark plug socket of an engine block and defines an elongate male electrical connection nut standing proud therefrom over which a corresponding electrical connection of the earth lead may be easily and safely electrically connected. The spark plug engaging opening device further comprises exhaust ports through a side of the device for engine decompression during cranking.

Abstract: There is disclosed a spark plug testing kit allowing for safe and convenient testing of petrol engines comprising a spark observation device; a spark plug opening engaging device; and an earth lead electrically connecting the spark observation device and the spark plug opening engaging device. The spark observation device comprises a transparent observation chamber so as to allow for the viewing of the spark gap of a spark plug installed therein in use. The observation chamber is substantially airtight so as to substantially prevent or reduce the possibility of the inadvertent ignition of fuel. The spark plug opening engaging device is configured for engaging a spark plug opening of the spark plug once the spark plug has been removed for observation so as to substantially prevent debris from falling in through the opening and serve as an engine block electrical connection contact for the earth lead. Furthermore, the spark plug opening engaging device comprises at least one exhaust for chamber decompression.