Exam Question

An auxiliary engine experiencing continuous speed fluctuation, or 'hunting', under a steady load points to a fault in the speed control feedback loop. The primary component responsible for this is the governor. Each potential cause must be evaluated based on its ability to introduce instability into this control system.
### (a) The Quality of Fuel
**This is a plausible, though less common, reason for speed fluctuation.**
* **General Effect of Poor Fuel:** Typically, a consistently poor quality fuel (e.g., low calorific value, high water content, high viscosity) does not cause speed *fluctuation*. It results in a steady state of poor performance, such as loss of power, high exhaust temperatures, and smoke. The governor would compensate for the lower energy release by moving to a higher, but stable, fuel rack position to maintain the set speed.