单项选择题
A.a broken shaft on the freshwater pump
B.an excessive accumulation of scale exchanger
C.an incorrect thermostatic element operating range
D.lube oil in the cooling water
单项选择题 The amount of fuel delivered by a helical plunger fuel injection pump is controlled by （）
单项选择题 On a diesel engine equipped with a hydraulic speed control governor, hunting in many cases can be corrected by adjusting the （）
单项选择题 Which of the following adjustments is always required whenever the diesel engine governor oil has been drained and renewed?（）