El Paso herald. (El Paso, Tex.) 1901-1931, 1918-02-02
WHEN THE MOTOR MLSFIRES
Popular Science Expert Tells Herald Readers Why
It Does and How to Remedy the Faults
Valves Cause Some Trouble.

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NE Of the commonest Ills to
which the internal combustion
~ engine is heir, IS misfiring
Naturally this complaint varies in
malignancy, sometimes affecting
only one cylinder. sometimes more,
often being merely temporary. due
to some incorrect adjustment, again
being seemingly permanent and call
ing for drastic action
Obviously mlsfirins interferes with
the satisfactory operation OF the en-
CINE. It means that one or more
cylinders is not firing. so that those
remaining in operation are carrying
on all the work. IN a six cylinder
engine missing is not SO annoying as
I in a four, this is obvious. also 1t IS
I harder to detect. In an eight or i,
one Of the cylinders may be cut out
and the ordinary amateur driver VIII
never detect 1t. Missing is more easl-
/ ly detected at low sIeeds than at
I high, because the flow Of power when
I the engine is running slowly tends to
/ become jerky anyway and the jerk
| caused by q missing cylinder makes
I detection fairly easy.
In q general way the basic causes
Of misflring may be divided into three
/ classes those caused by carburetion
failures. those caused by ignition
| failures 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 proportional mixture; the
fuel mixture may be too weak or it
may be too strong, the effect will be
the same, missing. Under fairly sat
I H1~n Nrlr-T Hfn~ 4
the engine after being warmed up,
begins to mfsfire, Il may be assumed
that the mixture being fed IS either
too rich or too lean That Is the first
place to begin trying to correct the
trouble. Misfires caused by faulty
carburetion viii not be confined to
any one cylinder. AIisfiring will oc-
cur IN one cylinder. jump TO another
and make its appearance sporadically
IN all the cylinders. This IS obvious
because the same carbureter feeds
the same mixture to all cylinders.
Two ways OF altering the compost
ton 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
the fuel is altered When misfiring
creasing the amount OF air used II
this IS the cause OF the trouble, the
engine viii at once take hold again.
On the other hand II the fuel mixture
was TOO weak already, the missing
will grow worse Immediately. which
IS a sign to cut down the quantity Of
air being fed, until the engine be-
gins TO function properly. The
amount of air should always be Just
as large as the engine will assimilate
II may be that there is some me
ehanical trouble interfering to make
around the inlet manifold or valves
viii allow too much air 10 enter. The
float OF the carbureter may be leak
ing, or II may be stuck, the needle
valve may not be seating properly,
there may be water IN the fuel, dirt I
on the needle valve, dirt in the fuel
or an obstruction in the fuel line. It ]
frequently happens that an engine Z
may run well enough in low speeds, I
but begins missing as the speed in /
creases- When the carbureter has i
two different adjustments for the Diff /
ferent speed ranges, the obvious thing |
to do Is to try adjustment OF the /
upper range. In making adjustments /
or the carbureter, the needle should |
be moved Just q fraction OF an inch /
either way and the engine tried after i
each change. All adjustments should /
be made while the engine Is hot.
Aasfiring caused by ignition faults I
IS fairly easy to locate. because II 1
usually is in the same cylinder. To /
test e suspected cylinder for ignition 1
the spark plug is short cir
Quilted with q screWdriver or similar /
instrument. When the plug is shorted.
with no difference being noticed in /
the operation of the engine. that cyl
inder is the guilty one. It may be /
that further inspection will show I
the spark plug at fault; II may be 3
earbonized, the points may be too far
apart or may be burned. the fnsula-
ton may be cracked. At any rate re-
placement of the plug Is the remedy. II
II the rlug IS found very oily at the /
bottom this may be causing the mis-
firing. The oil may have worked its 4
way past faulty piston rings or there II
may simply be too much oil IN the 4
III
II the spark plug Is found to be 4
all right, the wire should be traced II
right back to the distributor and all II
Insulation breaks should be repaired n
On the way. Should the wire be Il
whole, the trouble may be IN the dis
tributor; the distributor arm may 4
The segment or the segment may be
iirty. The distributor cap must be
and all segments should be
cleaned, and so should the distribu-
tor arm II battery system IS used, Il
he short arm. known as & tripper.
N4ALA IT'S INTO LnE AQLC4E4 EOLQE.
nay be worn. The connections OF
he ignition coil should be kept clean
md bright, but the car owner should
lot attempt to explore the mysteries
II that part. In the Ford system,
which employs four unit coils, the
Tibrator points may have gotten out OF
adjustment The coil connections 70
he commutator must be kept tight
md clean or missing may occur.
II the battery Is weak misfiring IS
Utmost certain to result II the bat
cry terminals are loose or corroded
he flow Of current may be so re-
itricted that missing will occur, and
he engine may even stop fiat.
The valve system IS frequently the
eat OF misfiring troubles. a stick
ng inlet valve will cause backfiring
md II the exhaust valve sticks, the
cylinder viii not fire at all. the
harge escaring by that outlet. In
.Ear.a.l-- A....--l L. 4. !