Page:Motors and motor-driving (1902).djvu/173

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IGNITION IN PETROL ENGINES
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hooks, provided for this purpose, inside the engine bonnet, to hold the methylated spirit required. Some automobilists dispense with the use of methylated spirits for the preliminary heating, and merely flood the burner with petrol allowed to run through gently, and setting alight to it keep the flame constant until the burner becomes heated. This method is to be deprecated, as very liable to ruin the paint on the engine bonnet.

Burners sometimes 'jump' this usually happens when first lit and not sufficiently heated. Time should be allowed for them to become thoroughly heated before attempting to start the car.

How to Extinguish a Burner.—When putting out burners blow them out with a length of rubber tube and allow them to cool down until the petrol flows freely through them, then turn off tap.

Faulty Burners.—When the flame burns yellow or on one side, it is because the burner is choked by some foreign body lodging in the nipple, and preventing the spirit from having free exit.

The best remedy is to put in a new burner at once, which should always be carried ready for use; the old burner may then be examined at leisure. When it is desired to remedy a faulty burner, the wick should be withdrawn and a 'pricker' run down the stem and out at the hole in the nipple, care being taken not to injure or enlarge the hole. Small particles of soot and dust in petrol are causes of trouble in gravity burners. When cold, and the petrol turned on for a moment, the jet should leap up straight at the tube; if it quivers or is on one side there is something lodged in the nipple. The nipple must be removed and cleaned. Tight wicks, so frequently supplied by manufacturers, prevent the free flow of spirit; loose wicks are useless, as they are at once pushed up to the end of the stem by the pressure of the petrol, and stop the hole; the wick should be a good fit, neither too tight nor too loose.