单项选择题
Operating a propulsion diesel engine at less than 30% of designed normal load for prolonged periods will result in （）.
A.decreased fuel consumption per brake horsepower B.more complete cylinder scavenging C.extended valve life D.carbon formation on combustion chamber surfaces
单项选择题 A dirty fuel oil filter element can be detected by （）
单项选择题 The major cause of fuel pump and injection system problems is （）
单项选择题 A diesel engine should not be operated at low loads for long periods of time because（）
