Spark Plugs Tell A Story
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Normal Spark Plug The porcelain should be a light tan or gray. |
Carbon Fouled Plug Has soft, black, sooty deposits indicating an improperly tuned engine. |
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Worn Out Spark Plug This plug has been in the engine too long. Note the large gap and worn out center electrode. This plug can misfire and cause stumbling and loss of power. |
Oil Fouled Plug Has wet-looking, black deposits indicating bad rings or valve seals. |
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Heavily Damaged Spark Plug Indicates possible detonation. Cylinder should be watched between services. Not only can the plug be damaged, but the engine as well. |
Bridged or Almost Bridged Spark Plug Caused by excessive carbon or oil build up on the spark plug. When the gap is bridged, the cylinder goes dead. |
