Question 42 UFIV01 - Chief Engineer - UFIV

The Correct Answer is C **Explanation for Option C (Correct):** Option C, **Kerosene or diesel fuel**, is typically acceptable for cleaning fuel strainer elements. These fuels are light petroleum distillates chemically similar to the diesel fuel being filtered, and they possess sufficient solvency (they are "petroleum-based solvents") to dissolve or wash away common contaminants like sludge, varnish, and particulates without harming the metal components or leaving residues incompatible with the engine's fuel system. Using the same fuel type (diesel) or a closely related, readily available product (kerosene) is standard practice aboard vessels for this routine maintenance task. **Explanation for Incorrect Options:** * **A) White mineral spirits:** While mineral spirits are petroleum-based solvents often used for degreasing, they can sometimes leave a residue (especially if not fully volatile) that might contaminate the diesel fuel system. They are generally heavier and less suitable than kerosene or diesel fuel for internal fuel system cleaning where fuel compatibility is paramount. * **B) Perchlorethylene or trichlorethylene:** These are chlorinated solvents, not petroleum-based solvents. They are powerful degreasers but are highly regulated due to toxicity, are usually expensive, and are not recommended for cleaning fuel system components because they can potentially attack gaskets, seals, or certain metals, and their residue may be incompatible with diesel fuel. * **D) Benzene or toluene:** These are aromatic hydrocarbon solvents that are highly effective but are also highly volatile, extremely toxic, and known carcinogens. Their use is strongly discouraged in confined marine environments for routine maintenance due to significant health hazards (inhalation risk) and fire risk, making them an unacceptable choice compared to safer, effective alternatives like kerosene or diesel fuel.