单选题About the jacket water, that of the auxiliary engines usually（） is circulated by pumps, and the main engine usually （）A an engine-driven；as wellB an engine-driven；has an independent pumpC an independent；as wellD an independent；has an engine-driven pump

Indirect cooling of fuel injector nozzle holders for diesel engines is accomplished primarily by

A.heat conduction into the injected fuel oil

B.heat conduction into the water jacket wall

C.water circulation through passages in the holder

D.fuel oil circulation through passages m the holder

The main propulsion diesel engine jacket water temperature rises above normal, with the raw sea suction and the expansion tank water level being normal. Which of the following problems is most likely the cause?

A.Faulty thermostatic bypass valve

B.Eroded zinc pencils in the heat exchanger

C.Steam formation in the expansion tank

D.Excessive leakage from jacket water pump seals

A.filtering

B.centrifuging

C.depositing

D.operating

When using a fuel with a higher than normal sulfur content in an auxiliary four stroke diesel engine, you may

A.maintain higher than normal jacket water temperature

B.change the lube oil more frequently than normal

C.maintain a higher air-box temperature than normal

D.maintain a higher air-box pressure than normal

If an auxiliary diesel engine coolant temperature is higher than normal, but the thermostat is determined not to be defective, you would suspect a/an

A.cavitation erosion in the water jackets

B.excess corrosion inhibitor in the coolant

C.dirty jacket water cooler

D.defective turbocharger