USCGQ
Log in Start free
USCGQ
Toggle sidebar
Home
Engine
Motor Plants and Auxiliary Boilers
Start practicing

Engine · 1,433 questions

Motor Plants and Auxiliary Boilers - USCG Exam Questions

Diesel engine theory and operation, fuel and lubrication systems, starting and reversing, and auxiliary boilers.

Every question below is a real U.S. Coast Guard exam question with four choices. Answer one and the correct choice is revealed instantly, with the USCG reference and illustration where the question uses one.

Random question Start at question 1 Build a timed exam

All Motor Plants and Auxiliary Boilers questions

Questions 1–100 of 1,433 · page 1 of 15

  1. #1 The process of supplying a diesel engine cylinder with air at a pressure greater than atmospheric is called __________.
  2. #3 Which of the listed types of superchargers will NOT have a volumetric capacity proportional to engine speed?
  3. #4 The relative air pressure in the inlet manifold of a turbocharged diesel engine is usually __________.
  4. #7 Why will a turbocharged diesel engine produce black smoke if excessive additional load is applied too quickly?
  5. #10 The device shown in the illustration is commonly used to __________. Illustration MO-0080 illustration
  6. #17 The power consumed during the scavenging process of a diesel engine is known as the __________.
  7. #18 Corrosion inhibitors and/or soluble oils are added to diesel engine cooling systems to __________.
  8. #19 Ethylene glycol, when used as a coolant in a closed cooling system for a diesel engine, is more advantageous than untreated raw water because it _____...
  9. #20 The expansion tank for a diesel engine closed cooling system is designed to maintain a constant head on the system and __________.
  10. #28 A three-way thermostatic control valve regulates the diesel engine cooling water temperature by passing a portion of the water __________.
  11. #29 What would be considered a normal temperature increase between the inlet and outlet jacket cooling water of a medium or high-speed diesel engine opera...
  12. #30 An electric heater built into some smaller diesel engines is used to __________.
  13. #32 The temperature at which an adjustable bellows type thermostatic valve operates is determined by __________.
  14. #34 Which of the following reasons represents why the designed compression ratio of a gasoline engine is lower than that of a diesel engine?
  15. #35 In the starting process of a diesel engine, the main object is to attain the compression conditions sufficient to __________.
  16. #37 Diesel engines are classified as reciprocating internal combustion engines because they __________.
  17. #38 The highest pressure in a diesel engine cylinder normally occurs __________.
  18. #40 Which of the terms listed below represents the operational speed at which excessive engine vibration is created?
  19. #45 Which of the following is an example of a solid bearing?
  20. #46 The proper location for journal bearing oil grooves is __________.
  21. #49 The linear motion of a diesel engine piston is converted into the rotary motion required to drive gears, propeller shafts, and generators by the _____...
  22. #50 Connecting rods in a diesel engine are used to connect the __________.
  23. #52 Before starting a diesel engine, you should always __________.
  24. #53 Which of the listed diesel engine operating conditions should be checked immediately after any diesel engine is started?
  25. #54 Before starting a diesel engine that has an engine driven lube oil pump, you should __________.
  26. #55 When attempting to restart a warm high-speed engine, which of the following reactions can you expect?
  27. #56 A normally operating diesel engine is shutdown by __________.
  28. #58 Babbitt is a metal alloy commonly used for lining __________.
  29. #59 Which of the following methods is used to securely fasten the Babbitt lining of a reduction gear bearing to its shell?
  30. #62 One advantage of electromagnetic slip couplings is __________.
  31. #63 What type of reduction gear would most commonly be used with twin medium-speed propulsion diesel engines driving a single shaft?
  32. #64 Reduction gear casings are vented in order to __________.
  33. #65 Which of the statements represents a characteristic of the thrust collar in a Kingsbury thrust bearing?
  34. #67 What is the function of the main thrust bearing?
  35. #73 Fuel oil discharged into the diesel engine cylinder is atomized at the __________.
  36. #75 The main advantage of unit injectors over other fuel injection systems is __________.
  37. #76 Fuel injection pumps using the port and helix metering principle requires the use of a __________.
  38. #78 The amount of fuel delivered by a helical plunger fuel injection pump is controlled by __________.
  39. #79 Which of the listed substances can be satisfactorily removed from diesel fuel by centrifuging?
  40. #80 Whether using a centrifuge or a simple filter, oil cleaning and filtration will be the most effective when the oil is at a __________.
  41. #82 To minimize corrosion, fuel oil strainer disks, spacers and scraper blades are made of __________.
  42. #83 For a continuous operation diesel engine, a duplex filter unit would be the best arrangement because __________.
  43. #84 Cooling the intake air supplied to a diesel engine will __________.
  44. #85 A large, low-speed, main propulsion diesel engine uses sea water to directly cool the __________.
  45. #86 An increase in the air inlet manifold pressure of a diesel engine will result in a/an __________.
  46. #87 In a naturally aspirated diesel engine, the volume of air intake is directly associated with engine __________.
  47. #91 A naturally aspirated diesel engine at full throttle will have an intake manifold pressure __________.
  48. #93 A magnetic strainer is primarily used in diesel engine reduction gear oil systems to remove small particles of __________.
  49. #96 Which of the following statements is true concerning a main diesel engine oil cooler?
  50. #97 The lube oil cooler is located after the lube oil filter in order for __________.
  51. #99 The purpose of an oil mist detector in a main propulsion diesel engine is to warn of __________.
  52. #100 Which of the following problems could develop due to the accumulation of oil vapors in the crankcase of a diesel engine?
  53. #101 The possibility of a diesel engine crankcase explosion will be increased by operating an engine __________.
  54. #102 If a diesel engine has been stopped because of piston seizure due to severe overheating, the crankcase __________.
  55. #104 Lube oil pumps taking suction from the sump of most small marine engines are usually __________.
  56. #107 Which of the routine maintenance procedures listed is required for starting air receivers?
  57. #110 Where is the air charge for an air starting system stored?
  58. #111 An accumulator used in a hydraulic starting system is generally located between the __________.
  59. #113 Auxiliary diesel engine electric starting motors use __________.
  60. #114 Diesel engine electric starting motors generally require heavier duty motors and operate at higher voltages than comparable starting motors for gasoli...
  61. #116 Hydraulic starters are installed on many lifeboat diesel engines instead of comparable air start systems, because __________.
  62. #117 When an engine fitted with a hydraulic starting system starts up, the starter is protected from the higher speed of the engine by __________.
  63. #118 The purpose of the engine-driven hydraulic pump in an auxiliary diesel engine hydraulic starting system is to __________.
  64. #121 Auxiliary diesel engine electric starting motors use __________.
  65. #122 Starting systems for large, direct reversing, main propulsion diesel engines are usually __________.
  66. #125 In a medium-speed marine propulsion engine equipped with direct admission air starting valves, the cylinders without air starting valves fire first be...
  67. #126 The most common instrument used to measure diesel engine exhaust pressure is the __________.
  68. #127 In a diesel engine exhaust system, the cooling of the exhaust gases below their dew point, will result in __________.
  69. #128 One of the factors limiting the amount of load which can be put on a modern marine diesel engine is the __________.
  70. #129 Exhaust pipes for separate main propulsion diesel engines can be combined only when __________.
  71. #130 The exhaust system for a turbocharged diesel engine functions to __________.
  72. #132 In a coil-type forced circulation auxiliary water-tube boiler, __________.
  73. #133 Which of the following statements concerning fire-tube boilers is correct?
  74. #134 Bottom blow valves are installed on auxiliary water-tube boilers to __________.
  75. #135 The purpose of try-cocks used on an auxiliary boiler is to __________.
  76. #136 An exhaust gas bypass is installed on a waste heat boiler in order to __________.
  77. #137 The maximum pressure developed by a waste heat boiler is determined by the main engine exhaust __________.
  78. #141 Which of the following statements concerning fire-tube boilers is correct?
  79. #143 The tube sheets installed in a fire-tube auxiliary boiler are normally connected by __________.
  80. #144 Fusible plugs are installed in fire-tube boilers to __________.
  81. #145 Constant capacity, pressure atomizing, fuel burners designed to meet a wide variation in steaming loads on an auxiliary boiler, are __________.
  82. #146 The primary function of a flame safeguard system, as used on an automatically fired auxiliary boiler, is to prevent __________.
  83. #148 The pressuretrol which is installed on an auxiliary boiler senses steam pressure changes and __________.
  84. #149 A variable capacity, pressure atomizing, fuel oil burner functions to __________.
  85. #150 The solenoid valves in the fuel oil supply line to an automatically fired auxiliary boiler, are automatically closed by __________.
  86. #151 Control of the fuel oil metering valve in an automatically fired auxiliary boiler is accomplished by a __________.
  87. #152 If the cooling water temperature and the lube oil temperature in a diesel engine are too high, the cause can be __________.
  88. #153 If the raw water supply pressure for a diesel engine cooling system is below normal, you should check for a __________.
  89. #154 Antifreeze solutions containing ethylene glycol, should not be mixed with corrosion protection oils, as the resultant mixture __________.
  90. #155 In a closed cooling water system, which of the following problems can cause the water pressure to fluctuate?
  91. #156 How is the illustrated strainer element cleaned during engine operation? Illustration MO-0057 illustration
  92. #157 In a normally operating diesel engine, the main source of lubricating oil contamination in the crankcase is a result of the __________.
  93. #158 A dirty diesel engine oil filter element can best be detected by __________.
  94. #160 A dirty lube oil strainer can result in __________.
  95. #162 Scale and dirt accumulation in the waterside of a lube oil cooler will be indicated by a gradual increase in the lube oil __________.
  96. #164 In an operating diesel engine, pre-ignition can be caused by __________.
  97. #166 If fuel oil were being discharged from the waste water outlet of a fuel oil disk type centrifuge, operated as a separator, you should __________.
  98. #168 Heat damage to fuel injection nozzles can be prevented by avoiding __________.
  99. #169 One cause of diesel engine surging can be a result of __________.
  100. #170 Which of the following problems can occur if you continually fail to drain off condensate from a starting air receiver?

Motor Plants and Auxiliary Boilers questions: what to expect

Q How many Motor Plants and Auxiliary Boilers questions are in the Engine pool?

There are 1,433 Motor Plants and Auxiliary Boilers questions on this site, every one released by the U.S. Coast Guard or taken from the National Maritime Center's sample examinations, with its correct answer. The exam draws its Motor Plants and Auxiliary Boilers module from the same pool.

Q What score do I need to pass the Motor Plants and Auxiliary Boilers module?

Most USCG exam modules, including Motor Plants and Auxiliary Boilers, require 70 percent to pass. Rules of the Road modules require 90 percent.

Q Are these the real USCG Motor Plants and Auxiliary Boilers exam questions?

Yes. They are the published U.S. Coast Guard questions, matched to the National Maritime Center's 2026 sample examinations. Answer any question to see the correct choice, the USCG reference and the illustration where the question uses one.

Other Engine modules

About the Engine question pool

The Engine pool holds the current U.S. Coast Guard questions for engineering credentials, from QMED ratings through DDE and Assistant Engineer up to Chief. Answer any question to see the correct choice instantly.