BOGGED.

Auckland Star, Volume LVI, Issue 184, 6 August 1925, Page 7 (Supplement)

BOGGED.

Another very common difficulty in starting is the flooding, namel}-, having so rich or heavy a vapour in the cylinder that a spark cannot ignite it. Though the choke, the withdrawal '»f which allows a richer mixture, is a useful adjunct in starting, it can be over used, with the result that, rather than facilitate the starting, it makes -it more difficult. The wrong use of the choke "will produce flooding. Complaints of difficulty in starting in cold weather are general. The trouble lies in the fact that the engine is extremely cold, and the air taken into the carburetter is very cold also. As a result it takes from six to seven times as much petrol to make a mixture strong enough to fire, although once the engine has started and become warm, almost the normal quantity of fuel will suffice. The carburetter makers are faced with a difficulty which is not easily overcome without some adventitious aid, because the starting and slow running jet cannot supply the greatly increased quantity of fuel for starting from cold, and at the same time ,provide an adequate fine mixture when once the engine is warm. Right Use of Choke (Strangler) On a cold morning the strangler .should be brought into operation and the engine should be turned quite slowly once or twice by hand, with the switch" off, in order to save- the batteries when -the. engine is usually ■ exceptionally stiff. Then the switch should be turned on and the engine swung rapidly by hand, or the starting moto.r.used, or a combination of . both methods employed. Quantities of petrol are thus sucked into the engine from the starting jet, aided by the main jet and compensator, and in .nine cases out of ten the engine will start almost instantly. Immediate action is then necessary, as unless the strangler is carefully handled, far too rich a mixture will be supplied to the cv-linders, and this is more difficult to deal with than too anaemic a mixture. Therefore the strangler should be opened as much as possible and as soon as possible, and only if the engine shows signs of faltering should it be closed until once more all cylinders arc firing evenly. Often it is better to open the strangler before switching on. On some carburetters, sealing the air intake for the. starting jet will suffice, but as a general rule it will not, because there is not sufficient air flow past the starting jet to- cause the latter to function unless the main air intake is also sealed. The Cause of Spitting. When a cold engine has started, often there is a great deal of spitting back into the inlet pipe when the engine is driving the car, a sure sign that the carburetter is not warm enough to supply the correct mixture. ' Spitting back, which is very often and quite incorrectly termed back-firing, may seem to be an "innocuous performance, but m fact is very dangerous, since a flame

engine obstinacy. The car can be placed in gear with the clutch held out until sufficient way has been got up to turn the engine. The clutch is then let in and the engine usually starts chugging. It must always be remembered that other auxiliaries have an effect detrimental or otherwise, when an engine is started. It is essential, for ."jxainple, that the magneto give a good spark at low speeds, which it often does only at full advance or as nearly so as is safe. Then the platinum points must separate properly and be clean, and the points of the sparking plug not too far apart. There must not be too many air leaks between the carburetter and the engine, which means that the washer between the mouth of the carburetter and that of the inlet, pipe must be in good condition and firmly clamped by the holding down nuts, that the inlet valve guides are not .much worn, and that both inlet .md exhaust valves are seated properly. Xo' engine will start easily if the compression is very weak, nor if oil os a viscosity quite unsuitable for winter work is used, because the engine then will be so gummy that it will be difficult for-it to'turn at a sufficient speed to produce an efficient spark at the plug. Similarly, the;starting motor,"if used, must be sufficiently big and powerful for its work, and must have clean brushes and commutator. A battery in its best condition is "essentials Batteries must not-be left unused for a month" even in a garage without being charged.