CARE OF SPRINGS
The springs of an automobile are in constant motion, and should be as carefully lubricated as the other parts of a car. The spring hangers by which the two halves of a full elliptic spring are joined, or by which a half elliptic spring is attached to the frame, are often provided with grease cups, but in the absence of these the parts should be frequently oiled. Once a season fresh lubricant should be applied to them. The leaves of a spring may usually be separated enough for this by jacking up the body, applying the jack to the frame; the springs will thus be relieved of the weight, and the leaves will separate sufficiently to permit heavy grease or graphite to be introduced between them by means of a table knife. If the springs are too heavy to permit this, they must be taken apart, which may be done by removing them from the car and releasing the clips by which they are held together. In reassembling a spring, it may be clamped in a vise, when the clip may easily be secured.
ADJUSTING VIBRATORS
In adjusting the vibrators, the best guide is the running of the engine. The musical tone that they make is misleading, for a difference in the steel of which the blades are made, or in the quality of the core, will produce a difference in the tone, and because two vibrators sound alike is not proof that they are producing equal secondary sparks. With a one-cylinder engine, the adjusting screw may be turned until the engine is running at its best, while at the same time there is the smallest spark between the vibrator contacts. The adjustment of the vibrators of a multicylinder engine is proceeded with along similar lines, all of the blades but one being held down, while the free blade is adjusted until the best results are obtained in the operation of the cylinder to which it corresponds, and the smallness of the spark between the vibrator contacts. When one is correct, it is held down and another released, this process being continued until all are adjusted.
MATCHING COILS
When coil boxes are so built that the units may be removed conveniently, as is usually the case, it often happens that the running of an engine may be improved by matching the coils and cylinders. A difference in the compression in one cylinder will often cause it to run better on one coil than on another, for no two coils will give identical results. Taking each cylinder in turn, and transposing the coil units in the box, the effect of each coil may be noted, and a combination found that will improve the operation of the engine.
ADJUSTING THE CARBURETOR
When adjusting a carburetor, it must be remembered that the proportion of liquid gasoline to air in a correct mixture is very small; because this is not well understood, a rich mixture is present far more commonly than a poor one. To begin at the beginning, close both the gasoline and auxiliary air inlets, and opening the gasoline adjustment a very little at a time, crank the engine with the relief cocks open until combustion is secured, the spark being retarded and the throttle nearly closed. When the engine runs, note the color of the flame that shoots out of the relief cocks. A poor mixture will produce a yellow flame, and a rich mixture a red and smoky flame, with black smoke at the exhaust and a smell of gasoline. The flame of a correct mixture is blue and hardly visible. On securing a correct mixture at low speed, advance the spark and open the throttle to speed up the engine, and the mixture will at once become too rich. Adjusting the auxiliary air inlet by weakening the tension of its spring will bring the mixture to approximately correct proportions. A more careful adjustment under road conditions can be obtained by adjusting the air inlet while the car is being operated, for the position of the carburetor is usually such that this may be done while standing or kneeling on the running board.
Faulty adjustment of the carburetor is often suspected when the real source is in the throttle or governor connections. The bending of a rod connecting the throttle with either the foot, hand, or governor control, or the wear of the joints, will throw the carburetor out, and the possible failure of these parts must be borne in mind accordingly.