If the suction pressure at the refrigeration compressor is below normal, the cause can be

A．refrigerant overcharge

B．overfeeding by the expansion valve

C．a restricted suction strainer

D．due to short cycling of the compress

[填空题] NO FLOW STAGE SUCTION PRESSURE PSLL-741表示（）。

[单选题]During the suction stroke, the piston is moving （）.A . inwardsB . outwardsC . downwardsD . upward

[单选题]The four strokes are called suction, compression, expansion and exhaust, but only （） stroke provides the power to drive the ship.A . suctionB . compressionC . expansionD . exhaust

[单选题]In the suction stroke air is induced into the cylinder （）In the compression stroke the air is compressed.A . by an fuel valveB . through an inlet valveC . with an exhaust valveD . from an outlet valve

[单选题]Four strokes consist of suction, compression, （） and exhaust stroke.A . combustionB . condensationC . chargingD . evaporatio

[单选题]Lube oil pumps taking suction from the sump of most small marine engines are usually （）.A . of the diaphragm typeB . of the centrifugal typeC . of the positive displacement typeD . independently driven by electric motor

[单选题]If the head pressure of a reciprocating refrigeration compressor is excessiveA．the relief valve should open before the high pressure cutoutB．the relief valve should open and allow the excess refrigerant to flow to the receiverC．the high pressure cuto

[单选题]（） the supercharge pressure is, （） power an engine develops.A . The higher；the moreB . Higher；moreC . Higher；littleD . The higher；the le

[单选题]Loss of lubricating oil pressure to the main propulsion diesel engine will actuate a/an _____.A．over-speed tripB．audible/visual alarmC．the ships/boats general alarmD．reserve oil storage tank

[单选题]The pressure differential across a diesel engine lube oil system duplex filter should be checked to ________.A．determine the need for filter cleaningB．measure any change in oil viscosityC．prevent damage to the filterD．determine the need for batch fil