Diagnosing Worn Spark Plugs
Removing and inspecting a spark plug will give you an indication of how it’s performing and how your engine is running. If you do not have experience removing and installing spark plugs, we strongly advise booking an appointment to have a professional assist you.
- Normal Wear: A sign of normal wear are brown/grey deposits on the side electrode.
- Carbon Build-up: Black soot on the electrodes and insulator tip indicates a carbon fouled plug, but can also indicate a dirty air filter, a rich air/fuel mixture, or a plug that is too cold for your application.
- Oil Build-up: Black oily deposits on the electrodes and insulator tip are indications of an oil-fouled plug. The source of the leak must be tracked down as it can indicate a more serious problem with the engine.
- Wet: A wet spark plug is a sign of a flooded engine and can be cleaned or simply left to dry.
- Burned: Obvious signs of heat damage such as melted electrodes or white deposits indicate a spark plug that is running too hot.
- Worn Electrodes: Worn electrodes are a sign that a spark plug has reached the end of its life cycle and needs to be replaced.
- Broken Electrodes: Broken or flattened electrodes can occur if the wrong type of spark plug is installed.
