According to years of experience in the maintenance of gasoline engine, by looking at the spark plug test ceramic core surface color can determine the gasoline engine failure, are described below:
1, ceramic core surface was white
The gasoline engine is working properly.
2, ceramic core surface was yellowish, reddish or reddish brown
Gasoline machine work is normal, spark plug ceramic core surface was yellowish, reddish or reddish-brown, is due to fuel, additives caused by the different.
3, ceramic core was brown black
Spark plug diagnostic tool was brown black, shell and side pole with a thick hard block of carbon deposition. There are two reasons: First, the gasoline engine burn oil, is due to oil from the piston ring or intake valve into the valve. Second, the reason for the spark plug itself, with the eyes to see the spark plug body broken or side electrode broken, there are not obvious from the appearance of the reasons can not see. You can use the method to check the flashover, the spark plug flat on the cylinder head, with the central high-voltage line from the spark plug test tool bolt 5 mm or so, and then dial the switch to see the spark plug gap flashover situation. If the spark is strong and blue and white, indicating that the spark plug normal, if the spark is weak or no spark, indicating that the spark plug itself is faulty, need to be replaced.
4, ceramic core was pale white
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Porcelain core pale, indicating spark plug tester overheating. In the multi-cylinder gasoline engine only appears in the individual spark plug, the spark may be hot (hot type) is too low, wrong, bad and other reasons; such as in a cylinder often pale, you should check the cylinder compression ratio Whether it is high, or check the spark plug around the water jacket is blocked. For the high compression ratio, should pay attention to whether the hot ignition phenomenon; if several cylinders at the same time there are pale white core, should consider the gasoline engine load is too large, cooling capacity and other reasons, should be used for higher calorific value of a spark plug.
5, ceramic core was slightly black
Was slightly black and covered with a thin layer of carbon powder, the shell surface and even side of the electrode are carbon deposition. This phenomenon if the long cold, low-speed operation after the emergence of a period of normal use will be eliminated. If the normal use of high working conditions, should be used for low calorific value spark plug. After the change should pay attention to the gasoline engine in the high-speed, high-load when there is no spark plug overheating and the center of a very burning, pull cylinder and so on.
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