Page:Motors and motor-driving (1902).djvu/182

150 Probably ninety per cent. of ignition troubles arise from faulty insulation.

Insulation Burnt.—A wire placed too close to an exhaust pipe invariably fails after a time, owing to the insulation becoming burnt by the heat of the pipe.

Insulation Cut.—A loose wire hanging against a sharp edge will invariably chafe through in course of time.

Insulation of Coil.—If the insulation of the coil breaks down it cannot be repaired on the road, it must be returned to the makers. A small ticking is usually audible inside when this occurs, when the current is turned on.

Coils placed too near the engine are liable to break down, as the heat is injurious to them. They must be fitted in a cool place.

Insulation Chafed.—Wires laid across moving parts, brake connecting rods, &c., will sooner or later give trouble.

Loose Connections.—All wires when joined together should be carefully soldered, the joints being afterwards insulated with rubber or prepared tapes. Never make a joint in the secondary wire. See that all terminals are tightly screwed up. Special attention should be paid to the 'earth' connections, which are a constant source of trouble. When connecting insulated wire, the insulation must be bared back, so that only the bare wire is attached. Wires sometimes become broken, and being loose make partial contact.

Dirty Connections.—Dirt is a non-conductor, and should be avoided on the electrical system, as on the rest of the car. Battery terminals frequently become corroded from acid fumes; they should be covered with vaseline, and require periodically cleaning. See that all connections at the coil are clean.

Broken or Defective-sparking Plug.—The porcelain may crack and the current jump across the fracture. The points may be sooty and require cleaning. They may be touching and require separating, or they may be too far apart. The usual distance between the points is about one sixty-fourth of