单项选择题
If the engine does not start on air, it may be due to （）
A.low compression of the fuel pumps B.incorrect timing of fuel pumps C.the starting air valves stuck D.air-locks in fuel oil pipeline
单项选择题 If the engine （） for a long period, there will be a danger of frost.
单项选择题 If the atomizer holes are enlarged beyond the makers recommended size, the atomizer must be （）.
单项选择题 If diesel oil in this tank is used, the （） of the oil must not exceed 120 degree F.
