MST-770 spark plug tester
Spark plug is one of the important components of ignition system, motor vehicles and other gasoline equipments' effective power depends largely on the performance of the spark plug, so it's said that the spark plug is the heart of the engine. Usually service life of spark plug is 15000km, service life of long-lived spark plug is 30000km. You need to replace the spark plug to a certain extent, so that cars will not reduce the power. This spark plug tester will tell you when to replace the spark plugs.
1. Precautions
1.1 The product is a high-voltage detector, so when the detectors are not in use, be sure to take the battery out to avoid danger.

1.2 If the discontinuous state appears in the process of using, that is normal, please loosen the switch with 3 seconds, you can continue to use.

2. Feature Locations

3. Test Principle
In automobile ignition system, the high-voltage ignition coil generates a high-voltage (10, 000 volts or more), and the spark plug diverts it from high-tension ignition coil into the cylinder engine, spark between the spark plug electrodes will ignite the mixture. The detector could tell the good spark plugs from the bad by the strength of the spark.

4. Test Method
1. Place the spark plug on the pedestal;

2. Power-on;

3. Press the key switch, the red LED will illuminate and the good spark plug will generate a strong spark and the bad will generate a faint one or not.

4. Loosen the key switch, take the spark plug down the tester by pinching the bottom of it.

5. Changing the Battery
This product can be battery-powered or use linear regulator, to replace the battery, follow these steps:

5.1Twist the screws on the backplane when the detector is off;

5.2 Remove the old battery;

5.3 Add two AA battery;

5.4 tighten the screws;

6. Accessories
1. 12V linear regulator

2. Operating Manual