单项选择题
A.leaking exhaust valves
B.an overloaded cylinder
C.a clogged injector nozzle
D.all of the above
单项选择题 In a bypass type lubrication system for a diesel engine, the dirty oil line to the centrifuge should be taken from the （）.
单项选择题 Theoretical perfect combustion in a diesel engine yields by-products of （）.
单项选择题 Which of the following devices is a common basic element with nearly all mechanical governors?（）