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If the detergent type lubricating oil being used in a diesel engine is black, the oil （）
A . must be centrifuged
B . must by filtered
C . must be changed
D . is holding finely dispersed carbon in suspensio
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If the analysis of used lube oil indicates a high content of iron particles, this could indicate（）
A . corrosive deterioration of a bearing
B . inadequate air filtration
C . excessive ring and liner wear
D . excessive cooling of lubricating oil
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Although lube oils used in the main lubricating service systems should have a relatively high flash point to avoid ignition, they can create smoke and fire hazards when they （）.
A . are exposed to a vacuum
B . come in contact with extremely hot surfaces
C . are reduced in temperature to just above the pour point
D . become extremely agitated or aerated
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Excessive lube oil consumption by a reciprocating air compressor can be caused by （）.
A、using a slightly dirty air filter
B、using oil having an excessive viscosity
C、intercooler or after-cooler leaks
D、carrying the oil level higher than normal
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Which of the listed conditions can be used to determine if lube oil has been diluted by fuel? （）
A . Viscosity is decreased
B . Octane number is altered
C . Pump speed is decreased
D . Blower’s speed is decreased
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If the cooling water temperature and the lube oil temperature in a diesel engine are too high, the cause can be （）
A . a dirty lube oil strainer
B . internal water leaks
C . an oil suction line restriction
D . excessive wears of the cooling water pum
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For a main diesel engine the lube oil in the bearings is drawn from （）, usually located in the bedplate.
A . a gravity tank
B . a sump
C . a vessel
D . a bottle
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When fuel oil is accidentally missed with lube oil which of the following processes can be used to separate them?（） Ⅰ.filtering Ⅱ.settling
A . Ⅰ only
B . Ⅱ only
C . either Ⅰ or Ⅱ
D . neither Ⅰ or Ⅱ
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Before starting a diesel engine that has an engine driven lube oil pump, the engineer should （）.
A . open the bypass line
B . cut in the lube oil cooler
C . pressurize the lube oil system
D . top off the expansion tank
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Lube oil filters remove contaminants more efficiently if the oil being filtered is （）.
A . under high pressure
B . under low pressure
C . heated to reduce viscosity
D . cooled to increase viscosity
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In a full flow type lube oil system, the bypass relief valve will lift due to （）
A . a clogged filter element
B . excessive lube oil pump discharge pressure
C . excessive lube oil flow
D . excessively hot lube oil
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If a used lube oil analysis indicates excessive fuel dilution, the lube oil should be （）
A . changed
B . centrifuged
C . filtered
D . settled
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Diesel engine lube oil can become contaminated as a result（）
A . the water produced during combustion
B . the sulfur in the fuel
C . unburned fuel oil
D . all of the above
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High lube oil temperatures developing in a diesel engine can result from（）
A . high oil pressure
B . excessive bearing end play
C . plugged oil control rings
D . engine overload
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With respect to the flow of lubricating oil through a diesel engine, the lube oil coolers are located after filters in order to （）.
A . allow filtration of less viscous oil
B . decrease the pressure drop across the filter
C . improve overall filtration
D . all of the above
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A lube oil sample taken from the main engine lube oil system has dark yellow opaque color.This is the result of （）
A . water contamination
B . mixing oils of two widely different viscosities
C . overheating
D . aeratio
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Lube oil cannot be efficiently filtered if its （）.
A . viscosity is too low
B . temperature is too low
C . pump discharge pressure is higher than the systems pressure
D . pump capacity is greater than the systems need
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In a diesel engine lube oil system, which of the following parts should be lubricated first?（）
A . Camshaft beatings
B . Main bearings
C . Piston crowns
D . Cylinder wall
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A sudden decrease in the diesel engine lube oil viscosity could be an indication of（）
A . loss of additives from the lube oil
B . carbon deposits in the lube oil
C . excessive centrifuging
D . excessive fuel dilutio
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The pressure differential across a diesel engine lube oil system duplex filter should be checked to （）
A . determine the need for filter cleaning
B . measure any change in oil viscosity
C . prevent damage to the filter
D . determine the need for batch filtratio
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A condition that can increase the foaming tendency of lube oil is （）
A . excessively high oil temperatures
B . water or moisture contamination
C . fuel dilution
D . life its cylinder relief vale
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Most large, low-speed, main propulsion diesel engines use duplex lube oil strainer to （）
A . decrease the time required between cleanings
B . removes all large and small foreign objects
C . ensure a positive flow of oil at all times
D . ensure that all lube oil has been treated twice
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Which of the following problems will occur if a disk-type centrifugal lube oil purifier is not properly primed prior to admitting oil flow to the bowl?（）
A、Contamination of the lube oil by emulsification will result
B、The lube oil will not be subjected to the proper centrifugal force
C、The lube oil will overheat and flash
D、Oil will discharge from the heavy phase discharge port and be wasted.
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Which of the following conditions could be a cause of excessive fuel dilution of diesel engine lube oil?（）
A . Leaking fuel injectors
B . Lower than normal compression
C . Delayed fuel injection
D . All of the above are correct
