單項選擇題Operating a diesel engine for prolonged periods, with a closed freshwater cooling system, at temperatures lower than the normal design temperature can cause （）.

A.the formation of sulfuric acid
B.a decrease in lube oil viscosity
C.a decrease in cooling water pH
D.a thermostat failure


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1.單項選擇題Improper maintenance of the fuel oil burners in an automatically fired auxiliary boiler, could result in （）

A.increased fuel consumption
B.increased feed water consumption
C.fuel pump failure
D.combustion control system failure

2.單項選擇題Which of the following conditions may need to be reduced when operating a large, low speed, main propulsion, diesel engine at low loads?（）

A.Injection pressures
B.Control air supply pressure
C.Cooling water flow through after-coolers
D.Lube oil temperature

3.單項選擇題The procedures recommended for auxiliary boilers having high salinity include （）.

A.treating with oxygen scavengers
B.securing the boiler and giving it a blowing down
C.increasing the pH
D.reducing the phosphate level

4.單項選擇題Excessive alkalinity of the water in an auxiliary boiler can cause （）.

A.caustic embrittlement of the boiler metal
B.acidic corrosion of the boiler metal
C.hard scale deposits on the boiler tubes
D.etching of the heat exchange surfaces

5.單項選擇題The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to （）.

A.assist in a quick cutoff of fuel injection
B.allow oil backflow from the injector to the helix
C.reduce fuel oil pressure between injection strokes
D.meter the quantity of fuel delivered