SETTING UP THE SYSTEM
In setting up a system of this description, the firing order of the engine must be ascertained, and this may be done by watching the order in which the exhaust valve stems move as the engine is slowly cranked. Piston No. 1 must then be brought to top dead center of the compression stroke, and about one thirty-second of an inch down on the power stroke, being stopped in this position. With the magneto screwed into place, the covers of the interruptor and distributor may be removed, and the armature revolved by hand in the direction in which it will be driven, until the interruptor opens, the spark control being in the most retarded position. A mark on the interruptor will come into line with a mark on the casing at the instant that the interruptor breaks contact. The magneto gear should then be meshed with the gear that drives it, and the lock nut set up.
The connection between the live end of the armature winding and the interruptor is arranged by the maker, but it is necessary to make connections between the magneto and the coil. A terminal will be found in the casing close to the stationary contact screw, and this is to be connected with one of the primary terminals of the coil, the other primary terminal either being grounded on the engine or the magneto, according to the construction. The moving part of the secondary distributor may then be connected with the secondary terminal of the coil. If the coil has but three terminals, two primary and one secondary, there are no further coil connections to be made, but if, as is sometimes the case, there are two secondary terminals, the free one is to be grounded on the engine.
An inspection of the distributor will show that the revolving part is beginning to make contact with one of the stationary points, and this point is to be connected to the spark plug of the cylinder in which the piston is at top dead center of the compression stroke. The next distributor point in the direction of rotation is to be connected with the spark plug of the next cylinder to fire, the remaining distributor points and spark plugs being connected in the order of firing.
Magnetos of this type are built to run in either clockwise or counter clockwise, and the two are not interchangeable. The direction in which the magneto is to be driven is indicated by an arrow stamped on the gear casing or end plate.
When the system is properly installed, the motor should start on a quarter-turn of the crank shaft, the crank being given a quick upward jerk. If it does not, the setting is incorrect, the connections are improperly made, or there is too great a distance between the points of the spark plugs. This distance should be one sixty-fourth of an inch.