Question 233Motor Plants - 1st Asst/Chief

The correct answer is D) dirt. The most common contaminant of governor hydraulic fluid is dirt. This is because the governor system is responsible for controlling the engine's speed, and any dirt or debris in the hydraulic fluid can interfere with the proper functioning of the governor, potentially leading to engine speed fluctuations or other issues. Maintaining clean hydraulic fluid is crucial for the reliable operation of the governor and the overall engine performance. The other answer choices are incorrect because: A) Air is not a common contaminant of governor hydraulic fluid, as the system is designed to be sealed and prevent air from entering. B) Acid is not a typical contaminant in governor hydraulic fluid, as the fluid is formulated to be non-acidic. C) Moisture is less common as a contaminant compared to dirt, which can more easily enter the system through various means.