How to Test if a Spark Plug is Good or Bad?
1 Answers
Testing methods for spark plugs are as follows: 1. Unscrew the spark plug and place it on the cylinder block, then test for sparks using a high-voltage wire. If there are no sparks or the sparks are weak, it indicates that the spark plug is leaking electricity or not working; 2. Let the engine idle and carefully listen for changes in engine speed and sound. If the changes in speed and sound are obvious, it indicates the spark plug is normal. If the changes are not obvious, it means the spark plug is in an abnormal state; 3. If the spark plug is severely eroded, with signs of pitting, black lines, cracks, or melted electrodes at the top, it indicates that the spark plug is damaged and must be replaced immediately; 4. If the spark plug is black as if smoked, it indicates the wrong heat range was selected or the mixture is too rich, with oil rising. If the spark plug is reddish-brown or rust-colored, it indicates the spark plug is normal.