Question 37 MODE02 - Assistant MODU Engineer

The Correct Answer is B **Explanation of why Option B is correct:** Option B states that the governor oil should be drained while the oil is **hot** and the governor should be flushed with the **lightest grade** of the same type of oil. This procedure is standard best practice for machinery lubrication systems for the following reasons: 1. **Draining While Hot:** Oil viscosity is lower when hot. Draining the oil immediately after the engine has been running (while the oil is still warm or hot) allows the oil to flow out more completely, carrying away maximum suspended contaminants, sludge, and wear particles that would otherwise settle as the oil cools. 2. **Flushing with Lightest Grade:** When flushing a sensitive mechanism like a hydraulic speed control governor, the goal is to wash away residual old oil and contaminants. A **lighter grade** (lower viscosity) of the correct oil type flows more readily into small passages, lines, and intricate parts of the governor (like the bushings, needle valves, and pistons) and has better detergent action to pick up contaminants, ensuring a more thorough cleaning before the fresh, specified operating oil is added. **Explanation of why the other options are incorrect:** * **A) The governor oil should be drained while the oil is cold and the governor should be flushed with the lightest grade of the same type of oil.** * **Incorrect:** Draining cold oil is ineffective. Cold oil is thicker (higher viscosity) and holds contaminants in suspension poorly, meaning a significant amount of dirty oil and settled sludge will remain inside the governor housing and piping after draining. * **C) The governor oil should be drained while the oil is hot and the governor should be flushed with the heaviest grade of the same type of oil.** * **Incorrect:** While draining hot is correct, flushing with the **heaviest grade** is wrong. A heavier (higher viscosity) oil would not flow easily into the small, critical passages within the governor, making the flushing ineffective at removing residual contaminants and old, dirty oil. * **D) The governor oil should be drained while the oil is cold and the governor should be flushed with the heaviest grade of the same type of oil.** * **Incorrect:** Both parts of this option are wrong. Draining cold oil leaves contaminants behind, and flushing with the heaviest grade prevents proper cleaning of the intricate internal components.