单项选择题
A.overloading the engine
B.low exhaust valve lift
C.excessive cylinder cooling
D.insufficient mechanical clearance
单项选择题 In a two-stroke/cycle diesel engine, the exhaust gases are expelled from the cylinder by the（）
单项选择题 If a diesel engine driving a generator turns over freely but fails to fire properly, the cause could be （）
单项选择题 One of the purposes for water cooling the exhaust manifold in marine diesel engine is to （）