COLD WEATHER STARTING

Ellesmere Guardian, Volume XLVI, Issue 3233, 3 July 1928, Page 2

COLD WEATHER STARTING

Petrol will turn to vapour at a temperature .of about 70 degrees in "the same way as water vaporises at 212 degrees. When steam strikes a surface colder than 212 degrees it will condense and again become water. In the same way vaporised i)etrol will condense if it comes in contact with a cold manifold after* leaving the carburetter.

The above is the reason why it is hard to start on a cold day. While the carburettor will do its work properly, the vapour, however, on the way to the cylinders, strikes the cold manifold and so condenses, with the result that practically nothing but air reach. 1 es the cylinders. When the engine is cranked it really travels v.cry slowly, and- so th\ suction and the movement of the mixture is slow, thus increasing th 6 chance for condensation. What can we do to start in cold weather. If, when starting, we make the mixture very rich, then, even though most of the gas condenses on the way to the cylinders, the chances are that enough will reach them to cause ' an explosion.' The explosion will make the engine revolve fast, causing a quick suction, and a quick movement, of the jnixture, thus not giving the gas a chance to^condense. Not only 'that,'but because of the friction between the previously condensed gas and the fast moving air, the condensed 7 " gasoline, which, is on the manifold, will be made to travel in the direction of the cylinders and so get itfto them, where, the temperature being high from the former explosion,- it \vill vaporise again.

To enrich the mixture , when starting, sometimes the carburetter is flooded by holding down the float, but perhaps more often much of the air is choked off by means of a choke valve. The valve is qperated by a wire fastened to a rod or lever , either on the instrument board or. steering .column, when a self-starter is furnished, or by ,a wire which passes through the radia|tor and terminates in a small ring or liook, when the engine is cranked, by hand. .

Kemember that the choke valve is a device for starting when the engine is cold. On- a hot day, or when the engine is hot after a long run and but a few moments standing idle, it would be better not to use the choke. When used on a hot day and hot engine . y it may cause the engine to choke; that is, become filled with so rich a mixture that it will not start.

Another cold weather device found on most 'cars is the '' season shutter.'' This should be closed in cold weather and open in warm. Few drivers pay any attention-to it, but it will pay to see that it is open when the weather is warm and closed when it is cold.