Five popular spark plug patterns for two-stroke engines.
Author Name: Eric Gorr
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| Heavy Carbon |
Heavy Carbon
This plug has heavy carbon build up. This engine had a blown crank seal on the
tranny side of the crank. Tranny oil entered the crankcase and was burned in the
combustion chamber. Engines like this will billow thick blue smoke out the
exhaust pipe.
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| Wet Fouled |
Wet Fouled
This plug is wet fouled. The spark plug's heat range is either too cold or the
carb jetting is too rich.
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| Sand Glazed |
Sand Glazed
This plug has a shiny appearance. The engine had a problem with air filter
sealing. Sand entered through the filter and into the engine. The high
combustion temperatures caused the sand to melt and form glass around the spark
plug.
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| Melted Aluminum |
Melted Aluminum
This plug has tiny globs of aluminum packed around the insulator. The engine
suffered a meltdown from ignition timing that was advanced too much. The heat
could not transfer from the spark plug fast enough and the center of the piston
melted causing the molten aluminum to collect on the plug.
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| Perfect Color |
Perfect Color
This is a perfect plug. The color is mocha brown so the carb jetting is optimum.
The first three threads are black signifying the plug's heat range is matched to
the application. There are relatively low deposits considering that this engine
was run on regular pump petrol.