The spring that keeps the revolving part of a timer in contact with the stationary part must be of sufficient strength to squeeze out the vaseline with which the timer is packed, as otherwise the grease will form an insulating film between them, preventing the flow of the current. The timer must be securely attached to its shaft, for if it is loose the contacts will be made at the wrong time, and the sparks will not occur in the combustion space at the correct intervals. All of its parts and connections should be as firm as possible. The rods with which the stationary part is connected to the control lever on the steering column should be provided with adjustments by which lost motion due to wear may be taken up. There are usually several joints in these rods, all of which may wear loose, and if there are no means by which they may be kept tight, the lever will move a considerable distance before the timer will respond. It is often possible to remedy this by placing coil springs in such positions that they take up the lost motion. A timer should be so set on the half-time shaft that the revolving contact is just touching the stationary contact when the piston is at its highest point in the cylinder on the compression stroke, the control lever being in nearly its most retarded position.
As dirt will interfere with the action of a timer, the cover should always be in place and tightly secured.
THE SECONDARY DISTRIBUTER
A secondary distributer will give trouble through loose contacts, dirt, or the splitting of the spark, the effect of the last being the passing of the spark from the revolving part to two or more contact points instead of but one. Particles from the carbon brush in wearing off may stick to the insulating ring between the contacts and form a path, or a strand of wire may project, producing the same result.
THE SWITCH
Loose switch parts will prevent the flow of the current or give a vibrating contact, and should be frequently looked after. If the switch is mounted on metal, as is occasionally the case, a loosening of the parts or the wearing of the insulation will result in a short circuit that is difficult to locate because the good condition of the switch is usually taken for granted.
GASOLINE TROUBLES
Commercial gasoline is frequently dirty, carrying particles of matter that will stop the fine passages and openings of the carburetor, or containing water, the presence of which will prevent the proper operation of the engine. Dirt may be removed by the use of a strainer made of fine wire gauze, and water may be separated by filtering the liquid through chamois skin, the gasoline passing through and the water remaining. It is advisable to have a strainer and trap placed in the piping that connects the tank with the carburetor to form the lowest point of the system, the gasoline passing through it and being cleansed of dirt and water.
THE TANK
The tank of a gravity feed system is always provided with a small hole or vent, usually drilled through the filling cap, through which air may enter to replace the gasoline that is drawn off in the running of the engine. If this hole becomes plugged with dirt, the escape of the gasoline will reduce the pressure in the tank to such an extent that further flow will be prevented, and the engine will stop with all of the symptoms of a lack of gasoline. On opening the tank for the purpose of investigation, the air supply will be renewed, and the engine will again run, to stop slowly as before. Clearing the hole will relieve the condition. This vent may also cause trouble in permitting water to enter and contaminate the gasoline, this being liable to happen when the car is washed.