Evening capital news. (Boise, Idaho) 1901-1927, 1919-03-30

l
SO tnat If one insulator becomes bro
Ken the other will prevent current
leakage.
In buying a plug you cannot tell by
looking at the insulator whether it is
good or not, because some cheap stone
looks just like good material. The
reliability of the maker is the thing to
consider.
Electrodes must be of such material
as not to be quickly affected by heat,
spreading and changing the gap size,
or burning away altogether. Nickie
wire, or similar high heat resisting
wire, usually is used, but the car own
er should take note of the thickness
of the electrodes. Thick ones last long
err than those of smaller diameter.
The commoner trouble with spark
plugs is caused by cracked insulatorsr
which allow of current leakage, causing
n poor spark or none at all at the sap.
Often one cannot tell by examining the
outside whether the insulator Is
cracked, because the trouble may be
in the hidden portion.
The only safe way is either to dis
piece type or test it by laying it on the
cylinder head with the plug cable at
tached. Then by cranking the engine
the gap may be watched for good
spark Cracks, except hidden ones,
may at once be noticed if the engine is
operating in a dark area; sparks will
be seen on the outside of the insulator.
Fouling is another plug trouble. The
term refers to the carbonizing OF the
electrode ends and bottom of the insu-
lator, resulting in a short circuit since
the current will pass through the car
bon instead of jumping the gap which
offers greater resistance. The carbon
deposits in troublesome quantity, be-
cause oil is splashed on the plug, ana
if the plug is of the sort which retains
the oil carbon forms there. 1t is usual
to hook shape the ground electrode SO
that oil will tend to flow away from
the gap.
When plugs become carbonized they
should be cleansed by immersing in
kerosene and then removing and
scraping the carbon off. The scraping
may be done with a knife, but care
parts, as this makes a good footing
for more carbon. When plug fouling
persists the cause should be gone in
to-probably leaky piston rings, too
much oil, too thin an oil, worn or pit
ted cylinders, etc.
The gap at the plug end must be
properly set. The usual gap is 1-32
inch, but this will vary slightly in diff
ferent engines. If the gap is too short
the spark may be too weak; if the
gap is too wide there may not be suf
ticient voltage to cause the current
to jump it. The gap is easily adjust
ed by slight bending of the found cleo
trode.
A spark plug should not be removed
Or taken apart unless it is giving trou-
ole or thought to be giving trouble.
squirt oil around the plug
Joints and watch to see if there is any
eakage of gas. Bubbles will appear
f there is leakage. At the shell to
cylinder joint this may be caused by
poor gasl<et dirty gasket, or worn
basket, or the plug not being screwed
n tight enough If the plug is of
wo parts the gasket at the joint may
lot be tight.
The right length of plug should al |
ways be used. 1t must have the points
ust below the Level of the cylinder
read and not in a pocket, where dead
:asses always exist. 1t also must not |
tick too far down. Find out the best |
ype for your engine and always ask
or that no matter what make you
ret. Avoid sensational types which
ire said to spark even if carbonized
md to give more than one spark. If
hey are carbonized the current will
70 through the carbon and not where
he maker says it will.
Never throw spark plugs haphazard
nto the tool box, where they may be
,ome cracked never throw an old
lug away. Save the old ones and buy
pare insulators or electrodes and save