4. Lesson 4. Starting difficulties

Notes:

1) ...failure of the engine to start on air ...	... неисправность в двигателе, связанная с пневмозапуском …
2) ...through alternate use of tanks for fuel oil and water ballast ...	... вследствие переменного использования цистерн для топ­лива и водяного балласта…
3) ... the only remedy is to stop using the fuel from that particular refinery.	... единственное средство — это прекратить употребление топлива именно с этого очистительного завода.
4) ... due to por design.	... вследствие плохой конструк­ции.
5)...air pockets in jackets ...	... воздушные пробки в рубашках цилиндров...
6) ...and wathfulness on the part of the engineers eliminates the other causes ...	а бдительность механиков исключает другие причины ...
7) ... a speed at which the twisting impulses imparted to the crank shaft ... coin­cide with ...	Скорость, при которой передающиеся на коленчатый вал скручивающие импульсы ... совпадают с ...

Failure of the engine to start on air may be due to one or more of the following causes: starting air pressure too low, incorrect timing of starting air valves, one or more starting air valves stuck, compression relief gear out of order, stop valve in air line closed, or, if starting after working on the engine, the jacking gear may still be engaged.

Operating troubles in general

Water in fuel oil. Water may get into the fuel oil by leakage through defective riveting of tanks, through alternate use of tanks for fuel oil and water ballast, or the fuel oil as delivered into the tanks may contain considerable moisture that will settle out. The degree of seriousness of the resulting troubles will vary with the amount of water in the oil, but among the possibilities are cracked heads and pistons, burned out exhaust valves, low compression due to wear of rings and liners, and irregular running of the engines.

Improperly refined oil.

Fuel oil must, during the refining process, be treated with sulphuric acid and this acid must later be neutralized with soda. If this neutralizing agent is not thoroughly washed out of the oil, its presence cannot be detected without chemical analysis nor is it removed by the filtering and straining methods ordinarily used on shipboard. When the engine is opened up after running on this insufficiently washed oil the entire surface of the combustion spaces in the cylinders will be found to have a coating of gritty material which looks and feels like sand but which is mostly sodium sulphate. It does not cause any immediate derangement of the engine but it does cause considerable wear of piston rings and cylinder liners. When such deposits are found the only remedy is to stop using the fuel from that particular refinery.

Loss of power or slowing down of engine

When this occurs the first possibility that should be investigated is hot bearings. Other causes are failure of fuel to one or more cylinders, derangement of valves of valve gear or a fall in cooling water temperature. A decided reduction of the sea water temperature will often be experienced when entering a river from the sea, passing out of the Gulf Stream or leaving tropical waters. When this occurs the cooling water supply should be cut down until the jacket water temperature is up to normal. A distinct loss in efficiency sometimes results from the idea that the jacket water should always be kept as cold as possible.

Cracked cylinders and cylinder heads

Cracks may result from unequal heating due to poor design, bad castings, air pockets in jackets, lack of cooling water and overloading. Modern practice in design and construction has greatly reduced the probability of cracking from the first two causes and watchfulness on the part of the engineers eliminates the other causes, so that cracked heads and cylinders are not nearly so common as they were in the early days of Diesel engineering.

Cracked crank shafts

During the early development period cracked crank shafts were so common that it was considered one of the inevitable hazards associated with Diesel engine operation. This trouble has become very rare, however, in modern practice.