Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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1.
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When “plastigauge”
is used to measure bearing clearances, check the:
a. | length of the
“plastigauge” | c. | drag on the rod | b. | width of the “plastigauge” | d. | thickness of the
“plastigauge” |
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2.
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Most diesel engines operate on
the principle of combustion caused by injection:
a. | air-fuel mixture into the
cylinder | b. | air into the highly compressed fuel in the
cylinder | c. | fuel into the highly compressed air in the
cylinder | d. | Air-fuel mixture ignited by a
spark |
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3.
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In diesel engines, typically,
the compression ratio is___ than the compression ratio in gasoline engines.
a. | lower | c. | doesn’t matter what type engine you have, both are
typically the same. | b. | higher |
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4.
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Where is the cylinder normally
worn the most by its piston?
a. | top inch of ring
travel | c. | center of ring
travel | b. | bottom inch of ring travel |
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5.
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“Oil doesn’t wear
out”
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6.
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Diesel combustion takes place
when fuel and hot air are ignited by a spark.
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7.
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What is the firing order of a
six cylinder engine?
a. | 1-5-3-6-4-2
| b. | 1-5-2-6-3-4
| c. | 1-5-3-6-2-4 | d. | 1-3-5-6-4-2 |
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8.
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Fuel and air are mixed in
diesel engine-
a. | inside the
cylinder | c. | in the super
charger | b. | before they enter the cylinder | d. | in the injectors |
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9.
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What transmits the motion of
the crankshaft to the camshaft?
a. | Connecting
rods | c. | Timing
gears | b. | Push rods | d. | Flywheel |
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10.
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A starter motor is different
from a “regular” DC electric motor in the following ways:
a. | The brush commutator is connected to
the output shaft. | b. | It needs a separate starter winding, since it must come to full running speed
before it engages the flywheel and the load is applied. | c. | It is designed for continuous operation, since some
engines, particularly diesel, are hard to start in the winter. | d. | It is designed to operate for short intervals under great
overload. |
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11.
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The two basic functions
of the ignition circuit are to:
a. | Induce high voltage at the spark
plug and reduce radio and television interference. | b. | Transmit high voltage to the cylinder of the engine and at
the same time eliminate microfarad interference with electronic diagnostic
equipment | c. | Step up low to high voltage surges and time these surges to the
engine. | d. | Step up high to low voltage surges and time these surges to BDC (Bottom Dead
Center) of the power stroke of the engine. |
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12.
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Technician “A” says
that an after cooler on a diesel engine is used to increase cooling system efficiency. Technician
“B” says that an after cooler on a diesel engine is used to increase engine
efficiency.
a. | A only | c. | B only | b. | both A and B | d. | neither A or B |
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13.
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Technician “A” says
that a closed center hydraulic system most commonly uses a variable displacement pump. Technician
“B” says that a closed center hydraulic system most commonly uses a fixed displacement
pump.
a. | A only | c. | B only | b. | both A and B | d. | neither A or B |
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14.
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One horsepower is equal
to
a. | The amount of heat it takes to raise
the temperature of one gallon of water 500 degrees Fahrenheit | b. | One thousand turns of a
crankshaft | c. | The lifting of a weight of 550 pounds one foot in one
second |
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15.
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When air is compressed in a
cylinder it is
a. | Ignited | b. | Heated | c. | Vaporized | d. | Stabilized |
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16.
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The warning lamp of a charging
system is activated by a:
a. | Variable resistance sending
unit | c. | Pressure
switch | b. | Temperature switch | d. | Difference in voltage |
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17.
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Both the alternator and
generator produce alternating current, which must be changed to direct current before it reaches the
battery. A generator changes the current from alternating to direct by:
a. | The action of the commutator and
brushes | b. | Utilizing a zener diode | c. | Utilizing NPN and PNP
diodes | d. | The relative action of the rotor and
capacitor |
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18.
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In a typical four-stroke cycle
engine having six cylinders, the crank on the crankshaft are set how far apart?
a. | 90
degrees | b. | 45
degrees | c. | 120
degrees | d. | 180
degrees |
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19.
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If a warning lamp (12V) will
operate when the ground circuit is bypassed with a jumper wire to ground, what should you check
for?
a. | Open ground
circuit | c. | Blown
fuse | b. | Defective buzzer | d. | Open circuit in the 12 volt supply wire to the
buzzer |
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20.
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In an alternator, alternating
current is converted to direct current by the:
a. | Stator | b. | Brushes | c. | Rectifier | d. | Regulator |
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21.
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What can cause excessive
voltage drop?
a. | Excessively large
wires | b. | Too much insulation on wire | c. | Excessive resistance in any part of the
circuit | d. | A short bypassing the load being
tested |
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22.
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Before attempting to start any
tractor always________.
a. | Put transmission in
neutral | c. | Depress
clutch | b. | Disengage PTO | d. | All of these answers are correct |
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23.
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If you are troubleshooting a
gear drive system, what would be the most likely cause of fins around the edge of the gear
teeth?
a. | Overspeeding | c. | Too much backlash | b. | Too little backlash | d. | Hardened gears |
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24.
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A common rail system is a type
of:
a. | Injection
system | c. | Intake chamber
| b. | Valve
system | d. | Accumulator
system |
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25.
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Technician A says that slow
hydraulics can be caused by an internal oil leak. Technician B says that excessive hydraulic system
pressure is caused by a faulty relief valve. Who is correct?
a. | A only | c. | B only | b. | both A and B | d. | neither A or B |
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