Page:Motors and motor-driving (1902).djvu/211

Rh governor. If this mechanism has been roughly fitted or has had much wear, I have often found that the ends of these springs should be slipped off their knobs for the engine to govern properly; and that if they are in place one cylinder may refuse to cut out at all.

Cause 4.—Of course if any of the delicate spindles, &c., connected with the governing mechanism be strained in any way, or are allowed to get dry for want of oil, the same trouble may be expected.

If the governor goes wrong at an awkward moment in the traffic, and the engine begins to race, it may be controlled by switching off and on, or retarding ignition, admitting an excess of air, or the exhaust-valve lifters may be thrown out by hand.

Regular.—If an unusual but regular puffing noise (external) is heard, which keeps time with the engine without apparently affecting its running, it is clear that an exhaust joint has given out somewhere between the exhaust valve and silencer. IF the rupture is near the engine, the exhaust gases may slightly interfere with the burners and the mixture, but otherwise no harm will be done to the motor, though the noise may frighten passing horses considerably.

A regular but unusual tapping coming from the engine indicates

i. Something loose or broken.

ii. Too much advance in ignition, or

iii. Engine about to seize through overheating.

If a squeak is heard anywhere instant attention should be paid to it, otherwise much harm may be done. A slight squeak is often very difficult to locate, and turns out sometimes to be perfectly harmless; a squeak has been traced to the rubbing of the bonnet against something inside it, to the shaking of the radiator, vibration of lamps, and such like causes, which, though trivial when found, are sources of great anxiety to a careful motorist.

I have had a distinct whistling sound produced by the rapid suction of air through a brass tap at each revolution of