One point that cannot be over sufficiently emphasized is the warning that only those who are thoroughly familiar with the magneto should attempt to disassemble it. Therefore every part should be studied, and its functional action fully understood before any repairs or adjustments are undertaken.

The manufacturers of magnetos have developed their product to a point of high efficiency and dependability, and if they are properly lubricated and washed occasionally to prevent gumming up, very little trouble may be expected from this type of ignition system.

Magneto Cleaning.—Magneto parts should be washed with gasoline as it has the ability to remove grease and dirt and evaporates rapidly leaving a perfectly dry surface. Care should be exercised to prevent fire, for the present grade of gasoline does not evaporate as readily as it did some time ago when refiners furnished a high test grade of fuel and the surface of the armature and indentures of the magneto may retain a pool or film which may be ignited by a short circuit, or from the breaker box, and cause a fire which would ruin the magneto. There is, however, little danger from fire if the gasoline is used sparingly, and each part wiped dry before reassembling the magneto.

It is considered a good point when the magneto has been taken apart to be cleaned to go over every part with a cloth dampened in kerosene, because gasoline leaves a very dry surface which is liable to rust. The bearings especially are most easily affected in this way.

The armature may be washed with a brush which has been dipped into gasoline, but should not be immersed as that would soften the insulation and cause it to rot.

The way in which the parts come off should be carefully noted in order to avoid trouble in reassembling, and the gears operating the distributor should be carefully marked to assure correct timing, which will result in a saving of time and trouble.

When the magnets are removed, close the ends with a file or piece of steel to prevent them from becoming demagnetized.

Magneto Repairing.—As previously stated, it is not likely that a magneto will require any further attention than the regular monthly oiling. Two or three drops of light sewing machine oil should be dropped into the oil wells which supply the bearings at each end of the armature shaft.

If any trouble arises that can be traced directly to the magneto, examine the breaker box mechanism first; the locknut at the point adjustment may have worked loose, and the points may be closed, or some abnormal condition may exist that has caused the points to pit and stick.

Breaker point adjustment varies from the thickness of a sheet of writing paper to one sixty-fourth of an inch; an adjustment anywhere between these two points usually results in satisfactory operation.

If the magneto does not function properly after the breaker box and external wire connections have been examined, the trouble is probably due to an internal short circuit, and repairs of this nature should only be undertaken by an expert magneto mechanic.

To remove the magneto, disconnect the high tension wires leading to the spark plugs from the distributor terminal posts, tag and number each wire to correspond with the number stamped below the post. If the engine fires 1-2-4-3, number three wire will be attached to number four terminal post. Then remove the ground wire and disconnect the universal joint and remove the metal strap, or the set screws, from the base.

To Time the Magneto.—Place the timing control lever in a fully retarded position; remove the plates from the distributor housing to expose the distributor brush and gear, then remove the cover from the interruptor housing to permit observation of the points, and rotate the armature in the direction which it is driven until the point begins to open. At this point mesh the distributor gear so that the distributor lever will just be touching one of the segments which connect to the distributor terminal posts.

Timing the Magneto with the Engine.—Rotate the crank shaft until No. 1 cylinder is up on dead center on the compression stroke; rotate the armature, with the spark lever in full retard until the distributor arm begins to make contact with No. 1 segment, and mesh the timing gear at this point.