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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 speed of a turbocharged diesel engine is maintained constant the turbocharger speed will ()
A . decrease until the engine speed increases
B . increase as the load increases
C . decrease as the load
D . increases remain unchanged
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If the diesel engine fuel injection timing is changed to delay the start of injection until the pistons are at top dead center, the engine will()
A . backfire through the air intakes
B . develop less power under load
C . have high firing pressures
D . lift its cylinder relief valve
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If a diesel engine fails to start,one of the likely causes is ()
A . low compression temperature
B . low ambient air pressure
C . high lube oil pump pressure
D . high fuel oil booster pump pressure
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If a diesel engines exhaust temperature is abnormally high, the cause could be()
A . too light of a load
B . injection timing is too early
C . overloading of the engine
D . too low of a compression ratio
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If a four-stroke/cycle diesel engine is started by injecting air into the cylinder, the pistons receiving the charge of starting air must be()
A . on the power stroke
B . on the exhaust stroke
C . at the end of the power stroke
D . at the start of the intake stroke
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A diesel engine will lose power if fuel injection occurs too early because the ()
A . fuel will not be properly atomized in the cylinder
B . ignition will be delayed due to low ignition temperature
C . maximum fuel expansion will occur on the compression stroke
D . fuel will ignite before top dead center
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If a diesel engine rotates slowly when cranked, but does not fire, the()
A . fuel control rack had admitted excessive fuel
B . engine speed does not match the fuel rack setting
C . engine has failed to reach its firing speed
D . starter pinion and ring gear contact is not correct
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If water is found in the crankcase of a diesel engine, the cause may be due to()
A . a cracked cylinder head
B . a leaky cylinder head gasket
C . a cracked cylinder liner
D . any of the above
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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 change
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A diesel engine may be hard to start if the ()
A . air intake is restricted
B . engine is cranked too fast
C . vibration dampener is faulty
D . exhaust back pressure is low
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If a single cylinder relief valve on a diesel engine lists frequently while the engine is running, the cause may be an ()
A . excessively late injection timing for each cylinder
B . incorrectly adjusted intake valve timing
C . incorrectly adjusted fuel injector
D . incorrectly adjusted intake valve clearance
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If a diesel engine runs roughly, which of the systems listed is most likely to be at fault?()
A . Fuel
B . Lubricating
C . Cooling
D . Ignitio
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If a four-stroke/cycle diesel engine is running at 1550 RPM, the speed of the camshaft will be().
A . 525 RPM
B . 775 RPM
C . 1550 RPM
D . 1800 RPM
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If a crankcase explosion occurs in a diesel engine, you should stop the engine and()
A . immediately open all crankcase relief ports
B . increase crankcase exhauster speed to draw cool air into the engine
C . allow the engine to cool naturally
D . increase crank case scavenge air to remove unburned gase
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The power output of a turbocharged diesel engine will drop if the cooling water flow through the after-cooler is interrupted because the ().
A . turbocharger stalls
B . exhaust pressure increases
C . air charge density decreases
D . scavenge effect increase
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The diesel engine is a type of ().
A、A. turbine engine
B、B. gas turbine
C、C. steam engine
D、D. internal combustion engine
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If an auxiliary diesel engine 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
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Charging-air pressure increases if there is incorrect combustion and drop in the () of the diesel engine.
A . machine efficiency
B . machinery efficiency
C . mechanical efficiency
D . mechanics efficiency
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If the coolant temperature of a closed cooling water system for a diesel engine gradually increases, the trouble usually is ()
A . a broken shaft on the freshwater pump
B . an excessive accumulation of scale exchanger
C . an incorrect thermostatic element operating range
D . lube oil in the cooling water
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If you suspect a diesel engine is misfiring due to air leakage into the fuel system, you should begin looking for the leak at the ()
A . fuel line connections to cylinder injection valves
B . gasket surfaces of the fuel oil filters
C . discharge fitting of the fuel injector pumps
D . suction side of the fuel oil tra
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Which of the following conditions will develop if the flow of ‘raw’ cooling water to diesel engine is obstructed?()
A . Air will enter the cooling system
B . Carbon will plug the water cooled exhaust manifolds
C . The jacket water temperature will rise
D . The lube oil viscosity will increase
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If a diesel engine is difficult to start and operates with the engine temperatures lower than normal, you should suspect that the ().
A . compression pressures are below normal
B . lube oil is diluted with fuel oil
C . cranking speed is too low
D . exhaust system is partially restricted
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The power output of a turbocharged diesel engine will drop if the cooling water flow through the after-cooler is interrupted because the _____.
A.turbocharger stalls
B.exhaust pressure increases
C.air charge density decreases
D.scavenge effect increases