Audubon County journal. (Exira, Iowa) 1884-1993, 1919-03-27
Are Coming the I'm.
porance Of Knowing How a Engine,


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 inch
is about the right space for most sys-
TENS where dry battery is used. This
is about equal to the thickness Of a
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 will often
be obtained when the gap Is not more
than one-fortieth or even one-fiftieth
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 half an
inch from any metal part connected
with the engine and in such q posi-
ton that the points are visible while
cranking the engine. Then turn the
engine over few times Cat least as
many times as there are cylinders)
and note whether spark jumps across
the space between the points. It is
not sufficient, however, merely to as
certain IL there is a 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
1t whether the spark is hot enough
or not, but if it is a heavy blue, or a
bluish-white, or a STAT" yellow one
looking like small flame, it is prob
ably all right. If very thin and green
ish or showing red, the chances are
1t 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 1t 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 ohsery-
ing its color and thickness.
It is also well to note the distance
the spark will jump, yet not advisable
to force it to jump too great a gap,
nor should the end of the wire be al
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 insula-
ton Of the coil. In the case of high
tension magnetos there is no danger
In this respect. as they are fitted with
safety spark gap which the spark
will jump, If for any reason the circuit
Is broken elsewhere.
knowledge Of just how much Of
spark one should obtain with each
kind Of ignition system Is frequently
Of great value in locating trouble, and
everyone who operates a gas engine
should make the allowed described tests
while the engine is In good order. If
one is not sufficiently familiar with
the looks Of good spark to tell by
mere observation whether 1t Is hot
enough, q rough test may be made
as follows: Place 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 1t is lying on the
engine in the position first mentioned,
then crank the engine. A good spark
will 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.
# the engine is equipped with a
make-and-break ignition system, in
which an igniter block is used instead
Of spark plug, 1t can be ascertained
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 good spark II
does not necessarily mean that the
| spark is given in the cylinder when
the engine is turned over. It may
be that the points Of the electrodes
inside the cylinder do not touch each
other when they should or are not
making a good contact, because car
bon. oil, dirt, ETC., have accumulated
J between these points. Therefore, If
j good spark occurs when the wire is
snapped across part of the engine
crank the engine until the movable
electrode is released and allowed to
fly back.
j Contact Not Being Made.
If one is not sure just when the
points Of the electrode should be touch.
ing, the engine may be cranked very
slowly for two full revolutions while
the end of the wire is repeatedly
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