The daily star-mirror. (Moscow, Idaho) 1911-1939, 1919-04-01

ment OF ASTlculiuIe.J
With all engines using spark plugs
1t is comparatively easy to ascertain
whether the ignition system is work
ing properly. Simply remove plug
and ascertain that the porcelain or
other insulating material on the inside
of the plug is not coated with carbon
and that the points are properly
spaced. One thirty-second of an men
is about the right space for most sys-
TENS where a dry battery is used. rms
is about equal to the thickness OF
worn dime. A wider gap will often
make starting difficult, especially when
the spark is rather weak or where
high tension magnetic is used. In the
latter case the best results VIII OFTEN
be obtained when the gap is not more
than one-fOrtieth or even 0ne-1fuetn
of an inch. Then re-attach the wire
and lay the plug so that the metal
base touches the engine casting, while
the end of the wire and the metal
tip of the plug are at least haf an
inch from any metal part connected
with the engine and in such posi-
cranking the engine. Then turn the
engine over a few times lat least as
many times as there are cylinders)
and note whether spark jumps across
the space between the points. 1t is
not sufficient, however, merely to as
certain if there is spark-it must
be hot enough to fire the compressed
charge in the cylinder 1t is, of course,
difficult to tell by merely looking at
it whether the spark is hot enough
or not, but if it is a heavy blue, or
bluish-white, or fiat" yellow one
looking like a small flame, it is prob
ably all right. If very thin and green
ish or showing red, the chances are
it is too weak to fire the charge. One
may familiarize himself with the as
pect of a good spark as follows:
Finding a Good Spark.
While the motor is in satisfactory
running condition loosen the nut on
the top of the plug while the engine is
stopped SO it will be easy to remove
the wire from the plug after the en-
CINE is started. Then start the en-
CINE and, by taking hold of the wire
where it is covered with insulation,
move the end of the wire very slowly
away from the center of the plug and
watch the spark jump, closely observ-
ing it's color and thickness.
1t is also well to note the distance
the spark will jump, yet not advisable
to force it to jump too great a gap,
c1,a fJa Of a l.
lowed to rest in position where the
spark cannot jump to the plug or the
engine while the engine is running as
this tends to break down the lnsula-
ton of the coil. In the case of high
tension magnetos there is no danger
in this respect, as they are htted win
a safety spark gap which the spark
will jump, if for any reason the circuit
is broken elsewhere.
Knowledge of just how much of a |
spark one should obtain with each |
kind of ignition system is frequently |
of great value in locating trouble, and |
everyone who operates gas engine !:
should make the abovedescribed tests /
while the engine is in good order IL /
one is not sufficiently familiar with I
the looks of a good spark to tell by
mere observation whether it is hot
enough, a rough test may be made
as follows: Place a thin piece OF
dry cardboard, such as an ordinary Wis
iting card, or three or four thicknesses
of dry newspaper between the points
of the plug while it is lying on the
engine in the position first mentioned,
then crank the engine. good spark
viii jump through these leaving a
tiny hole. A spark which will not do
this is too weak to jump the spark
gap in the cylinder under compress
sion.
If the engine is equipped with a
break ignition system, IN
which an igniter block is used instead
of spark plug, it can be ascertalned
easily whether the entire system, with
the exception of the igniter block, is
in good shape by disconnecting the
wire from the igniter block and snap
ping 1t across the corner OF the en- {
CINE casting or the end of the other ]
wire leading from the coil. But even {
though this gives q good spark 1T {
does not necessarily mean that the I
spark is given in the cylinder when i
the engine is turned over. 1t may |
be that the points of the electrodes
inside the cylinder do not touch each t
other when they should or are not |
making a good contact, because car i
bon, oil, dirt, ETC., haye accumulated {
between these points. Therefore, If i
/ good spark occurs when the wire is t
across part of the engine, V
rank the engine until the movable c
,lectrode is released and allowed to 0
ly back.
Contact Not Being Made. 0
If one is not sure just when the p
POINTS of the electrode should be touch I
ng, the engine may be cranked very n
Iowly for two full revolutions while L
he end of the wire is repeatedly /"
mapped across its connection on the n