National Maritime Center

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1 National Maritime Center Providing Credentials to Mariners U.S.C.G. Merchant Marine Exam (Sample Examination) Page 1 of 20

2 U.S.C.G. Merchant Marine Exam Illustrations: 9 Choose the best answer to the following Multiple Choice Questions 1. Which statement about diesel engine combustion is true? o (A) Combustion does not begin until the piston starts down on the power stroke. o (B) Maximum combustion pressure is reached before TDC. o (C) Turbulence in the cylinder causes a delay in ignition. (D) Maximum cylinder firing pressure is not developed until the piston passes TDC. 2. The diesel engine water inlet jumper illustrated is represented by the letter or number. Illustration MO-0122 o (A) "W" (B) "M" o (C) "N" o (D) "14" 3. Exhaust pipes for separate main propulsion diesel engines can be combined only when. o (A) space limitations prevent separately run pipes o (B) the engines are small auxiliary units (C) they are arranged to prevent gas backflow to each engine o (D) a waste heat boiler is installed 4. Auxiliary diesel engine electric starting motors use. o (A) 400 cycle per second motor-generator power (B) battery power direct current o (C) low amperage, high voltage AC power o (D) alternating current transformers 5. Which of the devices listed is installed on a diesel engine to isolate some of the crankshaft vibrations caused by rotational and reciprocating forces? o (A) Planetary gear set (B) Torsional vibration damper o (C) Friction clutch o (D) Air bladder clutch Page 2 of 20

3 U.S.C.G. Merchant Marine Exam Illustrations: 9 6. The item labeled #16 in the illustration is a stack of spring washers. Their function is to. Illustration MO-0062 o o o (A) absorb the high-pressure pulses developed during the fuel injection process (B) permit accurate stretch gauge measurement of bolt elongation during installation (C) prevent bolt failure by allowing limited movement of the injector when excessively high cylinder pressures are developed (D) maintain the same hold-down force on the injector regardless of varying engine operating temperatures 7. Cooling the intake air supplied to a diesel engine will. o (A) reduce mean effective pressure o (B) decrease average compression ratio o (C) decrease air charge density (D) increase peak power output 8. In a diesel engine, which type of wrist pin uses bearings in the piston bosses, but is fixed to the small end of the connecting rod? (A) Semi-floating o (B) Full floating o (C) Solid o (D) Fixed If choice A is selected set score to To minimize corrosion, fuel oil strainer disks, spacers and scraper blades are made of. o (A) brass o (B) copper o (C) iron (D) monel metal or stainless steel 10. The process of scavenging a two-stroke cycle diesel engine serves to. o (A) improve fuel flow volume (B) cool the exhaust valves o (C) reduce the intake air charge density o (D) increase the temperature of exhaust gases Page 3 of 20

4 U.S.C.G. Merchant Marine Exam Illustrations: The power/expansion stroke shown in the illustration is indicated by the diagram numbers. Illustration MO-0025 (A) 1 through 3 o (B) 1 through 4 o (C) 3 through 6 o (D) 4 through 6 If choice A is selected set score to A 4-stroke, medium-speed, eight cylinder, in-line diesel engine has a firing order of When performing routine valve maintenance, #1 cylinder is set at TDC in firing position. Which exhaust valves can be checked for proper valve lash? o (A) 1, 3, 2, 7 o (B) 1, 3, 2, 8 o (C) 1, 5, 2, 4 (D) 1, 5, 2, As shown in the illustration of the fuel injection pump, the component labeled "C" would be identified as the. Illustration MO-0061 o (A) control rack o (B) sleeve (C) plunger o (D) barrel 14. The main operating characteristic of diesel engines which distinguishes them from other internal combustion engines is the. o (A) method of supplying air o (B) cooling system (C) method of igniting fuel o (D) valve operating mechanism 15. Electric starting motors for diesel engines require high current for operation and. o (A) require a generator as a source of power (B) will carry a 100% overload for a brief period o (C) require a current/voltage regulator for proper operation o (D) will overheat if operated continuously over 10 seconds Page 4 of 20

5 U.S.C.G. Merchant Marine Exam Illustrations: Most large main propulsion diesel engines use a duplex lube oil strainer to. o (A) decrease the time required between cleanings o (B) remove all large and small foreign objects (C) ensure a positive flow of oil at all times o (D) ensure that all lube oil has been treated twice 17. A large, low-speed, main propulsion diesel engine uses sea water to directly cool the. o (A) cylinder heads o (B) exhaust valves (C) scavenging air o (D) injectors 18. When would the available energy of the exhaust gases of a two-stroke cycle diesel engine be insufficient to drive an exhaust gas turbocharger, resulting in the incorrect amount of air for combustion? o (A) During acceleration o (B) During operation at low load and speed o (C) During operation at rated speed, but low power output (D) All of the above 19. The expansion tank for a diesel engine closed cooling system is designed to maintain a constant head on the system and. o (A) provide an air-cushion o (B) reduce water turbulence (C) allow for an increase in water volume as the engine warms up o (D) reduce water temperature 20. What type of bearing is shown in the illustration? Illustration MO-0120 o (A) Axial/radial bearing o (B) Collar bearing o (C) Kingsbury thrust bearing (D) Michell bearing Page 5 of 20

6 U.S.C.G. Merchant Marine Exam Illustrations: Diesel engines driving alternators operating in parallel must maintain a set frequency regardless of load changes. The governor characteristic used to accomplish this is known as. o (A) actuation o (B) sensitivity (C) compensation o (D) promptness 22. How is the illustrated strainer element cleaned during engine operation? Illustration MO-0057 o (A) The drain plug is removed and the housing is drained. o (B) The housing is removed and the element is cleaned with a solvent. (C) The T-handle is rotated. o (D) The strainer element is removed, cleaned in kerosene or solvent, and dried with an air brush. 23. Fuel droplets injected into a diesel engine cylinder must have adequate penetration to. o (A) prolong the ignition delay period o (B) ensure the beginning of fuel injection (C) thoroughly utilize the air charge o (D) allow controlled fuel combustion 24. The fuel injector shown in the illustration is opened by fuel pressure acting upward on. Illustration MO-0059 o (A) part 33 o (B) part 36 (C) the needle valve o (D) the plunger 25. What type of marine engine has a fuel nozzle and combustion chamber located between two pistons in a common cylinder liner? o (A) Horizontal reciprocating (B) Vertical opposed-piston o (C) Single acting in-line cylinder o (D) Double acting in-line cylinder Page 6 of 20

7 U.S.C.G. Merchant Marine Exam Illustrations: Lube oil pumps taking suction from the sump of most small marine engines are usually. o (A) diaphragm type o (B) centrifugal type (C) positive displacement type o (D) eductor type 27. Starting a large low-speed propulsion diesel engine on diesel fuel during cold weather conditions will be made easier by. o (A) increasing the quantity of starting air o (B) increasing the lube oil pressure o (C) heating the engine fuel supply (D) heating the engine coolant 28. Which type of diesel engine fuel nozzle is shown in the illustration? Illustration MO-0059 (A) Multi-hole o (B) Open o (C) Self-cleaning o (D) Pintle If choice A is selected set score to The camshaft drive is designed to maintain proper camshaft speed relative to crankshaft speed. In maintaining this relationship, the camshaft drive causes the camshaft to rotate at. o (A) one-fourth crankshaft speed in a four-stroke cycle diesel engine o (B) one-half crankshaft speed in a two-stroke cycle diesel engine (C) crankshaft speed in a two-stroke cycle diesel engine o (D) two times crankshaft speed in a two-stroke cycle diesel engine 30. The valve stem expansion associated with engine warm-up is allowed for by the. o (A) valve springs o (B) hydraulic governor (C) valve lash adjusters o (D) cooling system Page 7 of 20

8 U.S.C.G. Merchant Marine Exam Illustrations: Which of the following is an example of a solid bearing? o (A) Thrust bearing o (B) Spring bearing (C) Piston pin bushing o (D) Turbo-generator turbine bearing 32. Which of the routine maintenance procedures listed is required for starting air receivers? (A) Frequent draining of accumulated moisture. o (B) Frequent testing of relief valves. o (C) A close watch on temperature to prevent fluctuations in pressure. o (D) Frequent cleaning to remove oil and foreign matter. If choice A is selected set score to The bore of a diesel engine cylinder describes the. o (A) swept volume of the cylinder (B) inside diameter of the cylinder o (C) piston displacement in the cylinder o (D) length of the piston stroke 34. If the jacket water temperature rises rapidly above normal in a diesel engine, you should FIRST. o (A) clean sea water strainer (B) reduce engine load o (C) call the chief engineer o (D) check thermostatic valve 35. In a normally operating diesel engine, the main source of lubricating oil contamination in the crankcase is a result of the. o (A) metal particles loosened by wear o (B) air when no air cleaners are used o (C) condensation of water vapors (D) combustion by-products removed from the cylinder walls Page 8 of 20

9 U.S.C.G. Merchant Marine Exam Illustrations: Precombustion chambers and energy cells in high-speed, small bore diesel engines all serve to increase. o (A) firing pressure o (B) ignition quality of fuel o (C) fuel/air ratio during compression (D) turbulence 37. Clearance volume scavenging in a turbocharged, four-stroke cycle diesel engine is accomplished. (A) during the valve overlap period o (B) with only the exhaust valve open o (C) at a pressure below atmospheric o (D) without cooling the cylinders or pistons If choice A is selected set score to Fuel injection systems are designed to primarily meter fuel, atomize fuel, and. o (A) create turbulence in the combustion chamber o (B) aid in completing cylinder scavenging (C) inject fuel at the proper time o (D) minimize fuel penetration into the cylinder 39. Load control on a diesel engine is accomplished by. o (A) regulating the speed of the turbocharger (B) regulating the amount of fuel admitted to the engine o (C) regulating the speed of the fuel oil transfer pump o (D) changing engine timing 40. Which of the following statements is true concerning the cetane number of diesel fuel? o (A) The cetane number affects the amount of injection lag. o (B) The cetane number is an indication of the fuel's viscosity. (C) Ignition lag is reduced with fuels having a high cetane number. o (D) The cetane number is of little significance in the combustion process. Page 9 of 20

10 U.S.C.G. Merchant Marine Exam Illustrations: In a diesel engine exhaust system, the cooling of the exhaust gases below their dew point, will result in. o (A) increased engine back pressure (B) sulfuric acid corrosion o (C) surface pitting of the turbocharger compressor blades o (D) moisture impingement on the turbocharger compressor blading 42. A diesel engine should use which type of lubricating oil? o (A) Low viscosity o (B) Cutting oil o (C) High grade vegetable oil (D) Detergent oil 43. The pinion gear shown in the illustration, is located. Illustration MO-0086 o (A) below #1 and #3 (B) between #1 and #3 o (C) below #2 and #4 o (D) between #2 and #4 44. The minimum fuel oil delivery pressure required for efficient injection depends primarily on the. o (A) degree of cylinder air turbulence (B) maximum pressure in the engine cylinders during injection o (C) quantity of the fuel to be injected o (D) duration of the injection delay period 45. What is the function of a diesel engine's stationary parts? o (A) To add power to the engine. o (B) To keep the engine firmly attached to its auxiliary pumps. (C) To maintain the engine's moving parts in their proper relative positions. o (D) To rotate the crankshaft. Page 10 of 20

11 U.S.C.G. Merchant Marine Exam Illustrations: Which of the following statements is true concerning the diesel engine cylinder head and valve mechanism shown in the illustration? Illustration MO-0013 o (A) The intake valve requires no adjustment. o (B) The illustrated engine utilizes a dry type cylinder liner. o (C) Intake and exhaust valves open simultaneously. (D) The rocker arm causes a valve bridge to open the valves simultaneously. 47. The small end of the connecting rod is attached to the piston with a. o (A) torque bushing o (B) crank pin (C) wrist pin o (D) sliding wedge 48. Which of the air intake systems listed will result in the lowest specific fuel consumption? o (A) Natural aspiration (B) Turbocharged o (C) Roots blower o (D) Piston blower 49. The purpose of an oil mist detector in a main propulsion diesel engine is to warn of. (A) a possible overheated bearing o (B) excessively high crankcase vacuum o (C) low cylinder oil pressure o (D) excessive carbon buildup in the lube oil If choice A is selected set score to One advantage of electromagnetic slip couplings is. (A) torsional vibrations are reduced o (B) torque increases with a decrease in excitation current o (C) the coupling rapidly responds to sudden changes of load o (D) excitation and induction power losses appear as a change in torque instead of rotational speed between the primary and secondary elements If choice A is selected set score to 1. Page 11 of 20

12 National Maritime Center Providing Credentials to Mariners MO-0013 N O P W V U Q T R S Adapted for testing purposes only from ALCO 251 Instruction Manual. ALCO. Page 12 of 20 Further reproduction prohibited without permission.

13 National Maritime Center Providing Credentials to Mariners MO-0025 Fig. 1 Fig. 2 Fig. 3 F A B E D G H I C J T Fig. 4 Fig. 5 Fig. 6 L N O S K R P M V Adapted for testing purposes only from Description of and Operating Instructions for Sulzer Diesel Engines, RND-M. Sulzer Brothers Limited. Page 13 of 20 Further reproduction prohibited without permission.

GUNTHER, Lubrication. Copyright 1971 by Raymond C. Gunther.

14 National Maritime Center Providing Credentials to Mariners A MO-0057 D C B 4/15/2015 Adapted for testing purposes only from GUNTHER, Lubrication. Copyright 1971 by Raymond C. Gunther. Further reproduction prohibited without permission. Page 14 of 20

National Maritime Center Providing Credentials to Mariners MO-0059 24 21 42 41 22 40 39

645E9 Turbocharged Engine Maintenance Manual.

15 National Maritime Center Providing Credentials to Mariners MO Adapted for testing purposes only from EMD 645E9 Turbocharged Engine Maintenance Manual. Copyright 1973 Electro-Motive Division, General Motors. Further 4/21/2015 reproduction prohibited without permission. Page 15 of 20

National Maritime Center Providing Credentials to Mariners MO-0061 7/23/2015 Adapted for testing purposes only from KATES/LUCK, Diesel and High

16 National Maritime Center Providing Credentials to Mariners MO /23/2015 Adapted for testing purposes only from KATES/LUCK, Diesel and High Compression Gas Engines, 3 rd edition Copyright 1974 by American Technical Society Further reproduction prohibited without permission. Page 16 of 20

National Maritime Center Providing Credentials to Mariners MO-0062 7/28/2015 Adapted for testing purposes only from Sulzer, Description of and

17 National Maritime Center Providing Credentials to Mariners MO /28/2015 Adapted for testing purposes only from Sulzer, Description of and Operating Instructions for Sulzer Diesel Engines RND-M Copyright Sulzer Brothers Limited Further reproduction prohibited without permission. Page 17 of 20

National Maritime Center Providing Credentials to Mariners MO-0086 7/21/2016 Adapted for testing purposes only from LUFKIN,

18 National Maritime Center Providing Credentials to Mariners MO /21/2016 Adapted for testing purposes only from LUFKIN, Marine Gears, Catalog No. MG-77 Copyright Lufkin Industries, Inc Further reproduction prohibited without permission. Page 18 of 20

National Maritime Center Providing Credentials to Mariners MO-0120 10/3/2016 Adapted for testing purposes only from Sulzer, Description of and

19 National Maritime Center Providing Credentials to Mariners MO /3/2016 Adapted for testing purposes only from Sulzer, Description of and Operating Instructions for Sulzer Diesel Engines RND-M Copyright Sulzer Brothers Limited Further reproduction prohibited without permission. Page 19 of 20

20 National Maritime Center Providing Credentials to Mariners MO /30/2016 Adapted for testing purposes only from EMD 645E9 Turbocharged Engine Maintenance Manual Copyright 1973 Electro-Motive Division, General Motors. Further reproduction prohibited without permission. Page 20 of 20

National Maritime Center

National Maritime Center Providing Credentials to Mariners U.S.C.G. Merchant Marine Exam (Sample Examination) Page 1 of 19 Choose the best answer to the following Multiple Choice Questions. 1. A Bendix