Arizona republican., 1918-02-03
INSPIRING COMMON ILL OF MODERN
 AUTOMOBILE

One Of the commonest ills to which | the internal combustion is heir, is misfiring. Naturally this complaint varies in malignancy, sometimes af- flicting only one cylinder, sometimes more, often being merely temporary, due to some incorrect adjustment, | again being seemingly permanent | and calling for drastic action.
 Obviously misfiring interferes with | the satisfactory operation of the en- zine. It means that one or more | cylinders is not firing, so that those remaining in operation are carrying 1 on all the work. In a six cylinder engine missing is not so annoying as in four. this is obvious, also it is 1 hardest to detect. In an eight or twelve, one of the cylinders may be l cut out and the ordinary amateur driver will never detect it. Misfir- ing is more easily detected at low 1 speeds than at high, because the flow yof power when the engine is running slowly tends to become jerky anyway
 and the jerk caused by a missing
 cylinder makes detection fairly easy.
 In general way, the basic causes
 of misfiring may be divided into three
 classes; those caused by carburetion
 failures, those caused by ignition fail
 ures and those caused by some de-
 rangement of the valve system.
 Misfiring due to carburetion causes
 may generally be traced to an i'm properly proportioned mixture; the
 fuel mixing may be too weak or it
 may be too strong, the effect will
 be the same, missing. Under fairly i af
 the engine after being warmed up, begins to misfire, it may be assumed
 that the mixture being fed is either t1o rich or too lean. That is the :, first place to begin trying to correct the trouble. Misfires caused by faulty carburetion will not be con fined to any one cylinder. Misfiring will occur in one cylinder. jump to another and make it's appearance sporadically in all the cylinders. This is obvious, because the same car ! buretor feeds the same mixture to all cylinders.
 Two ways of altering the com position of the fuel mixture are avail able, one by changing the position of the air control on the dash and the other by feeding more or less gas. In either case, the relative strength of | lne Iuel IS dIleTeU. W iien begins it is good practice to try in creasing the amount of air used. If | this is the cause of the trouble, the engine will at once take hold again. On the other hand, if the fuel mix ture was too weak already, the miss ing will grow worse Immediately, which is a sign to cut down the quantity of air being fed, until the engine begins to function properly. E The amount of air should always be just as large as the engine will as simulate.
 It may be that there is some me chanical trouble interfering to make the fuel mixture bad. Air leaks
 around the inlet manifold or valves will allow too much air to enter. The | float of the carburetor may be leak ing, or it may be stuck, the needle valve may not be seating properly there may be water in the fuel, dirt on the needle valve, dirt in the fuel or an obstruction in the fuel line. II frequently happens that an engine may run well enough in low speeds but begins missing as the speed in-
 creases. When the carburetor has two different adjustments for the diff ferent speed ranges, the obvious
 thing to do is to try adjustment of the upper range. In making adjust ments of the carburetor, the needle should be moved just fraction oi an inch either way and the engine tried after each change. All adjust
 ments should be made while the en- zine is hot.
 Misfiring caused by ignition faults
 is fairly easy to locate, because il
 usually is in the same cylinder TC
 test a suspected cylinder for ignition
 misfiring, the spark plug is shor1
 circuited with a screwdriver or simi-
 lar instrumet. When the plug l:
 shorted, with no difference being no
 ticed in the operation of the engine
 that cylinder is the guilty one. | | may be that further inspection vii ~ show the spark plug at fault; it may
 be carbonized, the points may be tot "A far apart or may be burned, the in ,e sulation may be cracked At an. e rate replacement of the plug is tn J., remedy. If the plug is found yer. J. oily at the bottom, this may be caus le ing the misfiring. The oil may hav'
 worked it's way past faulty pistol = rings or there may simply be tot = much oil in the crankcase.
 If the spark plug is found to b. \ all right, the wire should be traced | right back to the distributor and al | insulation breaks should be repairet
 on the way. Should the wire b. | whole, the trouble may be in tn
 distributor; the distributor arm ma, | not be making proper contact witt | the segment or, the segment may b \ dirty The distributor cap must b | removed and all segments should b \ cleaned, and so should the distribute
 arm. If battery system is used
 the short arm. known as the trippel
 which fits into the notched rotor, ma
 be worn. The connections of the ig
 hilton coil should be kept clean an
 bright, but the car owner should no
 attempt to explore the mysteries C
 that part. In the Ford system, whic
 employs four unit coils, the vibrato
 points may have gotten out of ad
 iustment. The coil connections
 the commutator must be kept tigf
 and clean or missing may occur. If the battery is weak, misfiring
 almost certain to result. If the bal tery terminals are loose or corrode the flow of current may be so re
 stricted that missing will occur, an the engine may even stop flat.
 The valve system is frequently u seat of misfiring troubles. A sticl
 ing inlet valve will cause backfirir
 and if the exhaust valve sticks, tf cylinder will not fire at all, u charge escaping by that outlet In properly timed valves will let u ui fuel leak away and if the sprint are weak, the valves will not clo: properly, with the inevitable resu