单项选择题The function of lubricating oil is to ()

A.maintain even distribution of bearing wear
B.maintain a constant oil temperature
C.maintain a pressurized film between moving surfaces
D.remove entrained water


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1.单项选择题Main propulsion engine lube oil sumps should be constructed ()

A.so as to never be integral lube
B.with a sloped bottom
C.only of nonferrous, noncorrosive metals
D.with drain/return lines terminating just above or at the designed normal level

2.单项选择题The ash content of a fuel oil is significant to the operating engineer because it ()

A.is an indication of the amount of noncombustible material present in the oil
B.indicates the quantity of energy released by burning a unit amount of the fuel
C.is useful for determining proper atomization temperatures
D.reflects the overall thermal efficiency of the fuel oil service system

3.单项选择题The shape of a cam on a diesel engine determines the valve’s ()

A.point of opening
B.speed of opening
C.lift from its seat
D.all of the above

4.单项选择题Which of the listed devices could be used as a ring groove tool during preparation for the installation of new rings?()

A.Steel brush
B.Fine emery cloth or steel wool
C.A section of the removed compression ring
D.A case hardened scraper

5.单项选择题The main source of fuel injection system malfunctions is ()

A.improper adjustments
B.contaminated fuel
C.coated fuel lines
D.excessive vibration

6.单项选择题The most crucial time for any bearing with regards to lubrication is ()

A.during low loads
B.after proper oil viscosity is reached
C.during starting
D.after cleaning filters

7.单项选择题If a main propulsion diesel engine hunts excessively at idle speed, you should ()

A.adjusts the idle speed control
B.drain and flushes the governor and replace the oil
C.adjusts the compensating needle valve

9.单项选择题Air bubbles in a hydraulic governor can cause ()

A.sluggish response
B.speed droop variations
C.isochronous governing
D.sensitivity increase

10.单项选择题On a diesel engine equipped with an isochronous governor, if the “speed droop” control is reduced to the “zero” setting, the engine ()

A.speed will drop drastically with any increase in load
B.will stop due to zero fuel supply
C.will stall upon application of load
D.speed will remain fairly constant despite load changes