Cooling water pumps driven by direct reversing diesel engines are usually of the straight impeller vane type pump with a concentric housing to ____________./provide cooling water flow when the engine is running either ahead or astern The expansion tank for a diesel engine closed cooling system is designed to maintain a constant head on the system and ___________./allow for an increase in water volume as the engine warms up Which of the following statements describes the function of an expansion tank in a diesel engine cooling system?/All of the above. The device allowing for the change in volume of the cooling water in a propulsion diesel engine closed cooling system is the _____________./fresh water expansion tank The highest pressure in any closed diesel engine freshwater cooling system is at the _____________./cooling water pump outlet In any diesel engine closed freshwater cooling system, the lowest pressure exists at the _____________./expansion tank atmospheric vent Maintaining the lowest possible scavenging air temperature at all times is not recommended due to the possibility of the ________________./formation of excessive quantities of condensate The outlet from an expansion tank of a closed freshwater cooling system should be piped to the ____________./jacket water pump suction line The expansion tank in a diesel engine closed freshwater cooling system is located at _____________./the highest point in the system A three-way thermostatic control valve regulates the diesel engine cooling water temperature by passing a portion of the water _____________./around the cooler In a diesel engine closed freshwater cooling system, the amount of coolant flowing through the heat exchanger is controlled by the _____________./thermostatic bypass valve Temperature control valves installed in the jacket cooling water system of a diesel engine, modulates the rate of water flow through the __________./heat exchanger The jacket water temperature in a diesel engine closed freshwater cooling system is normally controlled by _____________./the operation of the thermostatic valve Why do most temperature control valves in diesel engine closed freshwater cooling systems vary the flow of jacket water through the cooler instead of through the engine?/Changing the rate of flow in the jackets could cause localized hot spots. How much will the jacket water temperature normallyincrease between the inlet and outlet of medium orhigh-speed diesel engines?/10° to 20°F Using a cooling water temperature of 225°F (107.2°C), instead of 180°F (82.2°C) in an auxiliary diesel engine, will ______________./reduce the opportunity for the formation of sulfuric acid in the cylinder bore exhaust passages Operating a diesel engine for prolonged periods, with a closed freshwater cooling system, at temperatures lower than the normal design temperature can cause _____________./the formation of sulfuric acid As a general rule, the recommended operating water jacket outlet temperature range for medium and high speed marine diesels with closed cooling systems is ______________./180° to 199°F A closed freshwater cooling system is commonly used with marine diesel engines because the _____________./jacket water temperature is more easily controlled In a diesel engine closed freshwater cooling system where the cooling water pressure drop through the engine is 10 psig, and the pressure drop through the heat exchanger is 4 psig. The cooling water pump must produce a discharge head of at least _________/15 psig In a diesel engine closed freshwater cooling system employing a radiator, proper water temperature can be obtained by _____________./adjusting the radiator louvers Which of the listed effects would the film of alkaline chromate have on the metal surfaces of the cooling systemof a diesel engine?/Protects metallic surfaces from corrosion 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 _____________./has a lower freezing point and higher boiling point A diesel engine cooling water system with a pH factor of 3.0 indicates a condition of ____________./excessive acidity In a diesel engine cooling water system, a pH of 6.0 indicates a/an ______________./slightly acidic condition The pH value of water in a diesel engine closed cooling water system should be maintained between _____________./8.0 to 9.5 A two stroke diesel engine exhaust temperature will be lower than a four stroke diesel engine of the same displacement because the __________. I. mep is lower and the scavenging air is cooling the exhaust gases II. valve overlap in a four stroke diesel e/I only is correct The temperature at which an adjustable bellows type thermostat valve is set by ______./changing spring compression to oppose the bellows High diesel engine cooling water temperatures can be caused by _____________./all of the above High diesel engine cooling water temperatures can be caused by _____________./air in the cooling system Higher than normal jacket water temperatures occurring in all cylinders of a diesel engine can result from a/an __________./clogged sea suction strainer Which of the following problems will cause above normal cooling water temperatures in a diesel engine using a closed freshwater cooling system?/Eroded baffle in the cooler If the jacket water temperature of an operating diesel engine suddenly rises above normal, the cause can be attributed to _____________./a clogged raw water sea suction If the coolant temperature of a closed cooling water system for a diesel engine gradually increases, the trouble usually is _____________./an excessive accumulation of scale in the heat exchanger Some diesel engines are fitted with a thermometer in the cooling water outlet from each cylinder. If the cooling water temperature from all cylinders begins to rise above normal, you should suspect _____________./overloading in all cylinders You are operating a main propulsion diesel engine at a constant load when the jacket water temperature begins to rise. This could be caused by ____________./a piston about to seize Immediately after starting a diesel engine, normal raw waterand jacket water pressures are indicated. However, thejacket water temperature continues to rise. If there is nochange in the sea temperature, you should suspect _________./a jammed three-way thermostatic valve The main propulsion diesel engine jacket water temperature rises above normal, with the raw water sea suction and the expansion tank water level being normal. Which of the following problems is most likely the cause?/Faulty thermostatic bypass valve. Some diesel engines are fitted with a thermometer in the cooling water outlet from each cylinder. If the cooling water temperature from an individual cylinder begins to rise, you should suspect _____________./overloading of that cylinder One result of operating a diesel engine at light load with excessively low cooling water temperatures is a/an _______./increase in cylinder misfiring If the jacket water temperature in an auxiliary diesel engine cooling system is lower than normal, the probable cause is _________./faulty operation of the thermostat Prolonged operation of a diesel engine with a closed cooling water system, at lower than normal designed operating temperatures can _____________./cause sulfuric acid formation A faulty thermostatic bypass valve, in a diesel engine cooling system, can result in _____________./excessive time required for warming-up An emergency diesel generator cooling system is equipped with an automotive type thermostat. If the thermostat bellows loses its charge, the thermostat will _____________./close, and the engine coolant temperature will increase Cooling water pumps driven by direct-reversing diesel engines are usually ____________./straight impeller vane with concentric housing If the operating element of a thermostatic valve installed in a diesel engine cooling system malfunctions, it may result in ______________./improper temperatures Which of the following conditions will develop if the flow of "raw" cooling water to a diesel engine is obstructed?/The jacket water temperature will rise. Diesel engine exhaust gas temperatures can be used to determine individual cylinder _____________./performance All of the diesel engine cylinder firing pressures are normal, yet all of the exhaust temperatures are low. Which of the following situations is responsible for this condition?/Light load Which of the following factors tends to increase scale formation on the saltwater side of a heat exchanger used in a diesel engine cooling water system?/Operating the engine while maintaining a high sea water outlet temperature. Diesel engine exhaust temperatures may be used to indicate _____________./all of the above Cavitation erosion in the cooling water system of a diesel engine usually occurs at the pump impeller, and on the waterside of the _____________./engine cylinder liners High firing pressures and a low exhaust temperature in a diesel engine may result from _____________./early fuel injection timing If the raw water supply pressure for a diesel engine cooling system is below normal, you should check for a ____________./clogged sea strainer In a closed cooling water system, which of the following problems can cause the water pressure to fluctuate?/Air entrained in the cooling water. High exhaust temperature and black smoke exhausting from an auxiliary diesel engine can be caused by _____________./engine overload Which of the following problems can cause fluctuating pressures in the closed cooling system of a main propulsiondiesel engine?/Cavitation in the cooling water pump. Which of the following statements is correct concerning diesel engine cooling water systems?/At least two independent sea suctions are to be provided for supplying water to the engine jackets or to the heat exchangers. Maintaining the proper fuel oil temperature will result in _____________./improved atomization To successfully reduce an excessively high diesel engine exhaust gas temperature, you should _____________./reduce the load on the engine Which of the following statements is correct for the design and installation of diesel engine cooling water systems?/Drain cocks are to be provided at the lowest points of all cylinder water jackets. Coolant can be lost from a diesel engine jacket cooling water system by leakage from _____________./all of the above Failure to ensure proper venting of the cooling system of a diesel engine can result in ____________./local overheating and/or internal corrosion The knock occurring when a cold diesel engine is started and continues while running at low speed, but stops when the engine reaches normal operating speed and temperature, is _________________./normal for these conditions If a diesel engine's exhaust temperature is abnormally high, the cause could be ____________./overloading of the engine If the water level dropped rapidly in the expansion tank of a closed diesel engine cooling water system, you should suspect a _____________./leak in the primary cooling system Which of the following conditions can cause oil to accumulate in the cooling system of a diesel engine?/Defective oil cooler core. A diesel engine is operating with excessively high exhaust temperatures at all cylinders. To correct this condition, you should FIRST _____________./reduce the engine load One remedy for a high firing pressure, in addition to a high exhaust temperature in one cylinder of a diesel engine, is to ____________./adjust the fuel rack If a diesel engine is difficult to start and operates with the engine temperatures lower than normal, you should suspect that the _____________./compression pressures are below normal How are the pressure and temperature affected in a diesel engine cylinder during compression?/Pressure and temperature increase A diesel engine is operating under a normal load with low firing pressures and high exhaust temperatures. The most probable cause of this condition is ________________./a restricted exhaust manifold If the jacket water temperature rises rapidly above normal in a diesel engine, you should FIRST __________./reduce engine load A 16 cylinder main propulsion diesel engine is operating at 90% of full load. All cylinder exhaust temperatures are indicated at 950°F, except the No. 7 cylinder which is indicated at 1100°F. All fuel racks are at 21-22 mm except No. 7 which is at 16mm. /Replace and retime No. 7 cylinder fuel pump. In a diesel engine cooling system, the high temperaturealarm contact maker will be activated on excessively highwater discharge temperature from the ____________./engine jacket water outlet Cooling water pumps driven by direct reversing diesel engines are usually of the straight impeller vane type pump with a concentric housing to ____________./facilltiate bi-directional operation In a diesel engine jacket water cooler, with seawater cooling the fresh water, the ___________./jacket water pressure should always be greater than the sea water pressure If an auxiliary diesel engine coolant temperature is higherthan normal, but the thermostat is determined not to be defective, you would suspect a/an ___________./dirty jacket water cooler When one cylinder has a lower compression pressure and higher exhaust gas temperature than any of the other enginecylinders, which of the conditions listed will beindicated?/Leaky exhaust valve If the firing pressures in a diesel engine are high, although the exhaust temperatures are normal, the cause may be _____________./worn orifices in the injection nozzles Cooling water pumps driven by direct reversing diesel engines are usually of the straight impeller vane type pump with a concentric housing to ____________./to turn in either direction The device most commonly used to measure exhaust gas temperature of cyclinders is a _____________./pyrometer By comparing the exhaust gas temperature of each cylinder, the operator can determine if the load is balanced throughout the engine. The device most commonly used is a _____________./pyrometer High cylinder firing pressure, accompanied by low exhaust temperature, can result from _____________./excessively early injection timing Which of the conditions listed would cause simultaneous high cylinder firing pressure and low exhaust temperature?/Excessively early injection timing. When high firing pressures and low exhaust temperatures occur simultaneously in a diesel engine, this may be a result of ____________./early timing of fuel injection Operating a diesel engine under light loads and at low temperatures for an extended period can result in _________./formation of carbon on the intake and exhaust ports When starting a diesel engine at temperatures below 70°F, the frictional resistance to turning will be _____________./proportional to the lube oil viscosity Which of the following relationships should occur between the temperature developed in a combustion space, and the compression ratio of the engine?/Higher compression ratios create higher temperature. The diesel engine starter least likely to be affected by low ambient temperatures, is the _____________./hydraulic starting system A pyrometer is an instrument used to measure the temperature of the diesel engine _____________./exhaust Thermocouple pyrometers are used on large, main propulsion diesel engines to indicate the temperature of the ________./exhaust gases at various locations When the cold valve lash is less than that specified by the manufacturer, diesel engine valves, operating at normal temperatures, will ______________./close later than normal Low cylinder compression pressure and a high exhaust temperature may indicate ______________./leaking valves In a diesel engine exhaust system, the cooling of the exhaust gases below their dew point, will result in ____________./sulfuric acid corrosion One of the purposes for water cooling the exhaust manifold in marine diesel engine is to __________./reduce excessive heating of engine room If the jacket water temperature rises rapidly above normal in a diesel engine, you should FIRST __________./reduce engine load In comparing engines of equal horsepower, higher exhaust gas temperatures occur in a/an _____________./four-stroke/cycle engine You are operating a 16-cylinder diesel engine at 75% load, turning 900 RPM. All exhaust temperatures are between 900°F and 950°F, except the #3 cylinder, with an indicated reading of 750°F. All fuel rack settings are between 21 and 22 millimeters, with th/Increase the #3 rack setting and watch the exhaust temperature. | |
