Question 1

What is the approximate reduction ratio between armature shaft and output speed of a 39MT starter motor?

Accepted Answer

A)   1:1
B)   2:1
C)   3.5:1
D)   10:1

Question 2

If a heavy duty starter motor appears to spin when energized but the engine does not turn,which of the following could be at fault?

Accepted Answer

A)   worn pinion gear
B)   stripped flywheel ring gear
C)   defective starter drive assembly
D)   all of the above

Question 3

Which of the following connects the cranking control circuit with the starter motor high current circuit?

Accepted Answer

A)   ignition switch
B)   starter button
C)   starter relay
D)   starter solenoid

Question 4

What percentage of starter motors returned under warranty are tested to perform to specification by the OEM?

Accepted Answer

A)   100%
B)   80%
C)   50%
D)   30%

Question 5

A cranking current test on a diesel engine indicates low current draw.Which of the following faults would NOT be responsible for low current draw?

Accepted Answer

A)   partially discharged batteries
B)   low viscosity engine oil
C)   high resistance in the ground circuit
D)   high resistance in the insulated circuit

Question 6

Which of the following cranking circuit faults could cause slow cranking?

Accepted Answer

A)   weak batteries
B)   high viscosity engine oil
C)   corroded starter relay connections
D)   all of the above

Question 7

When does an energized diesel engine cranking motor produce peak torque?

Accepted Answer

A)   At close to stall RPM
B)   At the equivalent of 225 engine rpm
C)   At maximum cranking motor rpm
D)   After 15-seconds of cranking

Question 8

If you are bypassing a starter relay switch using a jumper wire,what component is being tested?

Accepted Answer

A)   starter solenoid
B)   ignition key
C)   battery bank
D)   starter relay/ mag switch

Question 9

What should be regarded as the maximum cranking time before resting a starter motor and allowing it to cool?

Accepted Answer

A)   15 seconds
B)   30 seconds
C)   1 minute
D)   2 minutes B

Question 10

Which of the following statements about a starter solenoid pull-in and hold-in windings is true?

Accepted Answer

A)   pull-in windings have more winding turns than hold-in windings
B)   pull-in windings use a heavier gauge than hold-in windings
C)   hold-in windings permit higher current flow
D)   hold-in windings are energized for less time during a cranking cycle

Question 11

What is the function of the overrunning clutch in a starter drive assembly?

Accepted Answer

A)   prevents starter motor damage from overspeed when the engine starts
B)   overruns until the starter produces enough torque to start the engine
C)   governs starter motor speed during cranking
D)   limits engine rpm during cranking

Question 12

When the ignition switch is closed,which of the following should happen first?

Accepted Answer

A)   cranking current flows through the control circuit
B)   the hold-in windings are energized
C)   the coil in the starter relay is energized
D)   the engine shuts down

Question 13

Technician A says that a neutral safety switch is designed to open circuit when a transmission is in Park range.Technician B says that a neutral safety switch is designed to close when the transmission is in neutral.Who is correct?

Accepted Answer

A)   Technician A only
B)   Technician B only
C)   Both A and B
D)   Neither A nor B

Question 14

Which of the following statements about current flow in a typical truck diesel engine starter motor are true?

Accepted Answer

A)   field coils are connected in series with the armature windings
B)   magnetic North and South field windings are wound in opposite directions
C)   all current flow though the field windings passes through the brushes
D)   all of the above

Question 15

Technician A says that the starter motor used to crank diesel engines can draw up to 400 amps of current.Technician B says that high resistance on the insulated side of a starter motor circuit would cause higher than specified starter motor current draw.Who is correct?

Accepted Answer

A)   Technician A only
B)   Technician B only
C)   Both A and B
D)   Neither A nor B

Question 16

Which starter solenoid winding has the greatest number of turns?

Accepted Answer

A)   pull-in windings
B)   hold-in windings
C)   they usually have an equal number of turns C

Question 17

Technician A says that the best method of locating high resistances in a cranking circuit is by using voltage drop testing.Technician B says that using an ohmmeter can locate high resistance starter cable.Who is correct?

Accepted Answer

A)   Technician A only
B)   Technician B only
C)   Both A and B
D)   Neither A nor B

Question 18

When using a carbon pile to load test a battery,which of the following should occur as you turn the control knob clockwise?

Accepted Answer

A)   resistance reading increases
B)   current reading increases
C)   voltage reading increases
D)   voltage and current readings increase B

Question 19

When used,where is a starter safety switch likely to be located?

Accepted Answer

A)   standard transmission
B)   automatic transmission
C)   either a standard or automatic transmission
D)   ignition key

Question 20

Which of the following is a disadvantage of a 42 MT starter motor?

Accepted Answer

A)   produces less torque than a 39 MT
B)   heavy
C)   will not crank high compression engines
D)   all of the above

Exam 9: Cranking Systems

What is the approximate reduction ratio between armature shaft and output speed of a 39MT starter motor?

Correct AnswerverifiedShow Answer

If a heavy duty starter motor appears to spin when energized but the engine does not turn,which of the following could be at fault?

Correct AnswerverifiedShow Answer

Which of the following connects the cranking control circuit with the starter motor high current circuit?

Correct AnswerverifiedShow Answer

What percentage of starter motors returned under warranty are tested to perform to specification by the OEM?

Correct AnswerverifiedShow Answer

A cranking current test on a diesel engine indicates low current draw.Which of the following faults would NOT be responsible for low current draw?

Correct AnswerverifiedShow Answer

Which of the following cranking circuit faults could cause slow cranking?

Correct AnswerverifiedShow Answer

When does an energized diesel engine cranking motor produce peak torque?

Correct AnswerverifiedShow Answer

If you are bypassing a starter relay switch using a jumper wire,what component is being tested?

Correct AnswerverifiedShow Answer

What should be regarded as the maximum cranking time before resting a starter motor and allowing it to cool?

Correct AnswerverifiedB

Which of the following statements about a starter solenoid pull-in and hold-in windings is true?

Correct AnswerverifiedShow Answer

What is the function of the overrunning clutch in a starter drive assembly?

Correct AnswerverifiedShow Answer

When the ignition switch is closed,which of the following should happen first?

Correct AnswerverifiedShow Answer

Technician A says that a neutral safety switch is designed to open circuit when a transmission is in Park range.Technician B says that a neutral safety switch is designed to close when the transmission is in neutral.Who is correct?

Correct AnswerverifiedShow Answer

Which of the following statements about current flow in a typical truck diesel engine starter motor are true?

Correct AnswerverifiedShow Answer

Technician A says that the starter motor used to crank diesel engines can draw up to 400 amps of current.Technician B says that high resistance on the insulated side of a starter motor circuit would cause higher than specified starter motor current draw.Who is correct?

Correct AnswerverifiedShow Answer

Which starter solenoid winding has the greatest number of turns?

Correct AnswerverifiedC

Technician A says that the best method of locating high resistances in a cranking circuit is by using voltage drop testing.Technician B says that using an ohmmeter can locate high resistance starter cable.Who is correct?

Correct AnswerverifiedShow Answer

When using a carbon pile to load test a battery,which of the following should occur as you turn the control knob clockwise?

Correct AnswerverifiedB

When used,where is a starter safety switch likely to be located?

Correct AnswerverifiedShow Answer

Which of the following is a disadvantage of a 42 MT starter motor?

Correct AnswerverifiedShow Answer

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B

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C

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B

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