How to Check to See if a Stator Is Bad

Four-wheel ATVs use a stator to charge the battery and power the ignition, lights and other accessories. The stator is simpler than an automotive-style alternator and typically does not produce enough output to charge the battery at engine speeds below 1,500 to 2,500 rpm. If your ATV battery is losing its charge, the problem could be a bad stator. A way to check this is to perform a running stator test, which will allow you to see how well the stator is working without the necessity of removing electrical parts.

Things You'll Need

  • Clamp-on current probe
  • Inductive tachometer
  • Multimeter
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Instructions

    • 1

      Remove the seat of the ATV to access the battery. Clamp the current probe on the positive battery cable.

    • 2

      Clamp the inductive tachometer pickup on the spark plug wire. Switch the tachometer on.

    • 3

      Plug the current probe cable into the multimeter. Switch the multimeter on and set it to "DC Millivolts."

    • 4

      Switch the ignition on and turn on the ATV's lights. Look at the multimeter display. If it does not show a negative number, remove the current probe. Turn the probe around and reinstall it on the cable so it points in the opposite direction.

    • 5

      Start the ATV's engine. Increase the engine speed as you watch the tachometer and the multimeter. The numbers on the multimeter display should gradually drop until they reach zero, then start to climb as a positive number. If the number does not drop to zero and become positive, the stator is not producing current.