（）diesel engines generally have two systems of lubrication:（

A.private

B.public

C.national

D.boarding

Crankcase explosions in propulsion diesel engines result from ____.

A.the splashing of lubrication oil by the crankshaft

B.the dilution of crankcase oil with particles of combustion

C.broken fuel lines spraying oil on the crankcase

D.the ignition of unburned fuel and air in the crankcase

Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because________.

A.The direction of pressure on the journal in four-stroke engine is continuously

B.positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engine

C.four-stroke engines usually utilize a heavier grade of oil than tow-stroke engines

D.Low-stroke engines usually consume less lube oil than four-stroke engines

Which of the following statements concerning the lubrication of diesel propulsionengines used in vessels over 300 gross tons is most accurate? ( )

A.Lubrication systems using engine driven lube oil pumps do not require any additionalindependent arrangement when such arrangements have been proven reliable.

B.The use of engine driven pre-lube pumps is permitted on vessels with propulsionsystems developing less than 500 shaft horsepower.

C.When forced lubrication is used for propulsion engines , one independently drivenstandby pumps is to be provided in addition to the necessary pumps for normaloperation.

D.Lubrication systems where two oil coolers are fitted require a minimum of twotemperature control devices which may be actuated by similar sensors.

Diesel engine electric starting motors generally require heavier duty motors and motors and operate at higher voltages than comparable starting motors for gasoline engines due to _____________.

A.higher speed required

B.flywheel-effect

C.lower starting temperatures

D.higher compression pressures