The answer to 'why is my generator buzzing noise' is that a buzzing noise from a generator is usually caused by a problem with the alternator or voltage regulator. This can be due to a loose connection, worn bearings, or a malfunctioning voltage regulator. The buzzing sound is often a sign of an electrical issue that needs to be addressed.
Some other common causes of a buzzing generator include a bad fuel pump, loose parts, or a problem with the engine. The buzzing may be accompanied by a loss of power or erratic voltage output. In some cases, the buzzing could be a sign of a more serious issue like a short circuit or damaged windings.