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單項選擇題

Which of the following problems represent one possible cause of high lube oil consumption in a four stroke diesel engine?（）

A.Worn intake valve guides
B.Pitted pre-combustion chambers
C.Loose valve tappets
D.High exhaust back pressure

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單項選擇題

Late fuel oil injection in a diesel engine can result in （）

A.fuel knock
B.increased power
C.low compression pressure
D.high exhaust temperature

單項選擇題

A crankshaft whose center of gravity coincides with its center line is said to be（）
Ⅰ.statically balanced
Ⅱ.dynamically balanced

A.Ⅰ only
B.Ⅱ only
C.both Ⅰ and Ⅱ
D.neither Ⅰ nor Ⅱ