Still another fellow had his car laid up for a week while he tried to find out what was the matter with it. He had sent magneto and coil to the factory for repairs and when they were returned to him a new type of coil was provided. He wired it up the best he knew how, but the engine would not start. Checking the wires over very carefully, they seemed to be placed properly, but a spark could not be obtained. Going to the source of the current, a test of the dry cells with an ammeter showed that they were dead. The fellow had lost a week’s use of the car because, having decided that the trouble was at the magneto or coil, he did not look anywhere else. He should have started at the battery to trace the current.
Another case which came under notice was where one of the headlights failed to light. A test showed that the current came to the lamp. To make sure the lamp was not at fault the one from the opposite side was substituted, but it would not light. The lamp was grounded by an extra length of wire and it worked all right. Then it was found that the ground wire, which was located back of the reflector inside the lamp, had become loose.
Most of these troubles point to the fact that a complete circuit is necessary to have an electrical current do its work. Therefore, when trouble occurs, the source of the current should be examined first and then the current should be traced through its entire path leading from and returning to the battery.
It might be a good idea for the owner on winter evenings to get out the wiring diagram of his car and trace the current from the battery through each light, through the ignition system, through the horn, and through every other electrical device used on the car, including the generator and starting motor.
Also it might be good practice for the owner to carry his wiring diagram with him when touring, so that the garage man, if there be trouble, may be helped to quickly locate it. But if the winter evenings be spent wisely in studying the electrical equipment, or even the entire car, or perhaps invested in a course of instruction at a good school, the owner might be independent of the garage man for the most part and besides have the satisfaction of knowing that when anything does go wrong he can find it and in most cases fix the trouble. The release from worry ought to be worth the time spent in learning how.
CHAPTER XIX
PUTTING THE KICK IN THE SPARK
Motors are a good deal like men. Very many of them, when everything is wide open and they are hitting it up at top speed, have excellent performance, but spit and sputter and knock a bit when compelled to travel at a lesser pace.
This is not moralizing, but the natural deduction from the complaints which are constantly received. A great many drivers want to know why it is they cannot throttle down the engine; they say it will pull well at medium or high speed, but skips at the lower speeds.
Where magneto ignition is used, this often may be overcome by adjusting the interrupter points for a little wider gap. That makes the interrupter points open a little earlier and causes the spark to occur when the magneto armature is in a more favorable position, and the spark therefore has more kick in it.
The interrupter points usually are adjusted for normal running speed, or a little higher than medium speed. Increasing the number of revolutions per minute of the armature causes a distortion of the magnetic field, which tends to follow the armature. This distortion is not so great at lower speeds. To overcome the distortion, which in effect twists the field around so that the points do not open at the period of greatest current potency, we must change the time when the points open and cause the spark; therefore, to get the best spark it is necessary to have the points open earlier. Widening the gap between the points accomplishes this.