单项选择题
A.an insufficient speed droop setting
B.an overloaded engine
C.clogged drain holes in the oil control rings
D.complete combustion
单项选择题 A dark exhaust from a running diesel engine can be caused by （）
单项选择题 What color exhaust will be exhibited when a slow speed two-stroke/cycle main propulsion diesel engine, designed to operate on light and heavy fuel oil, is operated on insufficiently preheated heavy fuel oil?（）
单项选择题 Combustion knock will most likely occur as a result of using a fuel with（）