Visual Inspection
- Normal operation
- Brown to Grayish-Tan with small amounts of White powdery deposits are normal combustion by-products from fuels with additives.
- Carbon Fouled
- Dry, fluffy Black carbon, or soot caused by the following conditions:
- Rich fuel mixtures. Check for leaking fuel injectors, excessive fuel pressure, restricted air filter element or incorrect combustion.
- Reduced ignition system voltage output. Check for weak coils, worn ignition wires or incorrect spark plug gap.
- Excessive idling or slow speeds under light loads can keep spark plug temperatures so low that normal combustion deposits may not burn off.
- Deposit Fouling
- Oil, coolant, or additives that include substances such as silicone, very White coating, reduces the spark intensity. Most powdery deposits will not effect spark intensity unless they form into a glazing over the electrode.