Question 110Motor Plants - 1st Asst/Chief
70% to passWhen changing over from residual to distillate fuel on a slow-speed diesel propelled vessel, you should limit the rate of temperature change of the fuel in order to prevent what operational difficulty?
ASeizing and scuffing of fuel pump plungers and injector needle valves due to thermal effects on close clearance components.
BDezincafication of the fuel in the mixing tank.
CSurging/hunting of the governor due to rack sticking.
DCarbonization in the fuel heater.
AI Explanation
The correct answer is A) Seizing and scuffing of fuel pump plungers and injector needle valves due to thermal effects on close clearance components. When changing over from residual to distillate fuel, the fuel temperature needs to be changed gradually to prevent thermal shock to the engine's fuel system components. Sudden changes in fuel temperature can cause the metal fuel pump plungers and injector needle valves to seize or become scuffed due to the differing thermal expansion rates between the components. This can lead to operational difficulties and potential engine damage. The other answer choices do not directly relate to the effects of rapid fuel temperature changes during the fuel changeover process.
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