THE TRUTH ABOUT MOTORS. SMALL LEAK—BIG FIRE

NZ Truth, Issue 1184, 9 August 1928, Page 15

THE TRUTH ABOUT MOTORS.

SMALL LEAK— BIG FIRE

Explosive Vapour Under Bonnet

QNE of the most frequent causes of fire m a car is the leaking of the carburettor or the pipes leading to it. ;

QUITE frequently the unions m the pipe between the vacuum tank and the tap are not leak proof, and during the period of rest the fuel, leaking out will result m the formation of explosive vapor surrounding the engine. t An exposed plug owing to a broken wire or dirty commutator can ignite this vapor with disastrous results. Some of these leaks are very insidious. It takes considerable time to locate them, since the petrol vaporizes almost as rapidly as it leaks out, and the surface may seem dry. But the inflammable gas is being made and is dangerous. A badly seating float chamber needle valve is a very frequent cause of petrol leaks which may be dangerous. When the engine is running this is not so serious, as the petrol may be drawn fast enough to prevent flooding. But when the engine is at rest the float chamber will overflow and the results may be dangerous.

This petrol-impregnated air may be ignited by a spark. Even the spark which may occur at the contact-breaker of the magneto or of the coil and accumulator system may cause a flare up if the air is carrying petrol fumes. ' This may occur after the car has been at rest with the engine stopped, and . on the first attempt to start the motor. Cases have been known where the. sparking of the brushes of the commutator have caused a flare up when petrol gas has been present under the bonnet or lying, as petrol gas will lie, m the apron under the engine. It is almost impossible to. guard against the chance of such a happening except by ensuring that petrol is not leaking anywhere. In the case of the garage the , same conditions arise. The car .left standing should have the petrol turned off. ■ ,