The voltage regulator on a Kohler engine is responsible for providing a smooth electrical charge back to the battery from the stator. When the regulator malfunctions, it can either drain the battery or cause an overcharging that can damage the battery or the wiring harness. Testing the voltage regulator is an easy process that takes about five minutes.
Place the device containing the Kohler engine on a hard, flat surface and remove the key from the ignition.
Inspect the battery. Make sure the positive and negative cables are tight and inspect the battery case and terminals for cracks. Open the electrolyte cells by prying off the top cap with the flathead screwdriver. Check electrolyte levels and add soft, clean water if needed.
Place a small load on the battery by turning the key to the ON position for 15 seconds. Turn the voltmeter on and turn the dial to 20 ohms. Place the black lead from the voltmeter on the negative battery post and the red lead on the positive post. The voltage should read 12 volts without the engine running. If lower than 12 volts, the battery is bad.
Start the engine and advance the throttle to the FAST position with the voltmeter still connected to the battery. The voltmeter should read a minimum of 13 volts; if it still reads 12 volts, the voltage regulator is bad.