Cleaning and Inspecting Sparking Plugs

The plug spanner must be handled carefully to avoid cracking the insulator. Make sure that it fits securely over the plug. After unscrewing the plugs see that the sealing washers do not fall off and become lost.

The most effective method of cleaning the plugs is the use of a garage plug-cleaning machine in which a high-pressure air blast carries a fine abrasive into the interior of the plug, effectively scouring the insulator, the inner walls and points.
When this is not possible the work can be done quite effectively at home with the aid of the Techniblaster plug cleaner, which operates on the same principle as the garage plug cleaner but in which the air pressure is obtained by connecting the cleaner to a tyre pump. Oily plugs should first be swilled out with petrol. About half a dozen strokes of the pump will clean the plug and the rubber connector can be disconnected from the cleaner and used to blow out any remaining abrasive from the plug. Grains that are trapped between the insulator and the interior of the plug can be dislodged with a stout darning needle or a short length of wire, hammered flat at one end. In passing it may be mentioned that some garage mechanics overlook this very important point.