STARTING DIFFICULTIES.

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

STARTING DIFFICULTIES.

V BACKFIRING AND CHOKING. ! X EFFECT OF CO—D "WEATHER. HINTS THAT MAY SAVE YOUR 'V TEMPER. >Sd There is nothing more provoking than iJ\ to be unable to start the engine, but Xi in a climate like that of the Dominion. Jm with considerable difference between the J? summer and winter temperatures, this will always be evidenced to a certain extent whatever the make of car.- The principle of starting is to have the mixyf* lure of benzine and air in the cylinder head of such a nature that it can be easily fired. jf Before going into a fairly detailed je explanation of starting difficulties, it )/' may be pertinent to explain backfiring and choking, two common contretemps Jj± that a driver has to contend with. A mf backfire in starting is caused by a premature explosion. That is to "say, the vapour in the cylinder is exploded before h the piston has reached the top of the fe cylinder; the explosion occurs, driving V! the piston back, and the engine backfires, turning the starting handle, if one is being used, the reverse way it is being turned. The results have unfortunately Jjs been illustrated only too often in the form of broken hands, wrists and arms, h and on occasions the handle has struck «> other parts of the body. The primary V! cause of this backfire is an advanced spark. Nine out of ten engines are h designed to fire at ordinary running speed just before the piston reaches the v% top of the cylinder, but for starting purposes it is desired to get the piston h right at the top. The advancing of the spark creates an explosion before the I piston has reached the top, and the I backfire results.

caused by the firing of the mixture in the inlet pipe flashes through the choke tube of the carburetter and may set light to any petrol iv the neighbourhood. For this reason it is unwise to flood the carburetter. It is true flodding may enrich the mixture sufficiently to obtain an easy start, but if the process is carried on too long there are certain to be pools of fuel about the engine and on the ground under the car. Flooding discreetly is another matter. Expedients in Starting. There are quite a number- of expedients in overcoming difficult starting. As mentioned above, though, it is unwise to llood the carburetter —it can be done judiciously. For instance, on cars with compression taps a small quantity of benzine can be poured into the cylinder direct and provided the spark is strong enough (and. of course, not advanced) the engine will usually start with a turn or two. This remedy, however, may lead to flooding, which is more difficult to get rid of and the plugs may even have to be taken out and dried. Another remedy is to suck it out by turning over the engine when it is not switched on. Quite a number of drivers who have engines with carburetters innocent of stranglers temporarily choke the air intake with rag, an effective procedure provided that the firing of the mixture in the inlet pipe does not set the rag alight. A cork which fits the choke tube, however, and is attached to the carburetter by a string or wire, is verymuch better than a string or rag, though both are temporary expedients. Extremely obstinate engines may be made to start easily by filling the radiator and jackets with hot water, or even placing rags soaked in hot water round the carburetter away from the air intake. Quite a good remedy, too. is to take out the plugs and heat them, thus assisting in vapourisation. People who have their cars garaged on a hill have a natural assistance in overcoming *he