Digital Multi-Meters come in two common varieties: Auto- Ranging, and Non Auto-Ranging. A non auto-ranging meter requires you to select a range of “sensitivity” for the given function you are using. For example if you want to measure resistance, you would need to select a range of up to 200 ohms, up to 20Kohms (20,000 ohms), 200Kohms, etc. An auto-ranging meter will automatically figure out the range and give you a measurement.
In order to turn a shaft with combustion, we need to convert not only chemical energy, but we need to convert a reciprocating motion into a rotational motion. The reciprocating motion is the engine’s piston moving up and down, and the rotational motion is the crankshaft turning. As you can imagine there is a lot of things moving all at once with drastic changes in direction and speed. This process generates a lot of unwanted vibration and movement as a by-product.
To measure voltage on a battery for example you first turn your meter to DC Voltage. Place the red probe on the positive terminal of the battery and place the black probe on the negative side of the battery or on a common ground. Your voltage will display on the screen.
To measure AC voltage for example on your engine’s stator, you first locate the two wires coming from the stator. Turn your DMM to AC Voltage. Place the red probe onto one of the wires, and the black probe on the other wire. You should read about 24 to 30 VAC.