GUARDING AGAINST FIRE
The education of automobile owners and chauffeurs is decreasing the
number of cars which go up in smoke, but there still are cases enough
to require a word of warning as to causes and prevention. Automobile
fires sometimes come from causes not ordinarily considered under the
control of the driver. However, a little extra caution in a few matters
will render the motorist practically free from danger.
Of course, the principal cause of automobile fires is from back-firing.
Without going into all the causes of back-firing, the chief one is too
lean a mixture fed to the cylinders. This will almost invariably cause
back-fire in starting. Really, the chief trouble comes in starting when
the engine is cold, and naturally this is most frequent in the winter.
When there is a back-fire a sheet of flame comes from the air intake of
the carburetor; if there is anything inflammable in that vicinity, it
is quite likely to take fire.
Gasoline vaporizes so rapidly that if there is gasoline in the drip pan
there is almost sure to be a sufficient mixture around the carburetor
to make trouble. As a matter of fact, the drip pan under the carburetor
should be so arranged as to allow any gasoline to be drained off before
it has had time to vaporize. Indeed, there ought not to be very much
gasoline in the drip pan at any time. If it comes from a leak in the
supply pipe or the connection to the carburetor, the leak should be
repaired. If it comes from an overflow of the carburetor due to poor
seating of the float valve, that should be taken apart and cleaned
so that the float valve will seat properly. These two things are
practically the only occasion for gasoline in the drip pan.
Another cause of fire may be in running for some time at extreme
speed. This usually will cause the exhaust pipe to become very hot,
sometimes to glow. The exhaust pipe in some cases is placed close to
the woodwork of the car, which may be set on fire. Particularly is this
true if the woodwork has an accumulation of grease and oil, and here
is where caution will have a beneficial effect. The owner who keeps
the woodwork free from oil and grease—cleans it off regularly and
thoroughly—minimizes the danger at this point.
The pipe also heats up when the engine is run with a greatly retarded
spark. Sometimes the pipe gets red-hot and it is an easy matter to
ignite the woodwork. Here again oil or grease would increase the
danger. The economical operator will not allow grease and oil to be
wasted in this way, aside from the fact that grease, oil, and gasoline
in drip pan or carburetor form a menace hard to overestimate.
Fires have been started occasionally by opening the muffler “cut-out”
in starting up. This is particularly dangerous when the car is in a
garage, where usually there are grease and gasoline spilled around on
the floor, giving off fumes and creating a danger zone. Occasionally
when the car is standing in the garage the supply line will drip a
little. It may be all right when the gasoline is flowing into the
carburetor regularly, but when it stands, a tiny drip will make a
considerable mixture under the car. A leak, so small as to be unnoticed
ordinarily, when continued over night will cause enough mixture to be
dangerous. If, to aid the engine, the operator opens up the “cut-out,”
there are quite likely to be some sparks flying out. Sparks and gas
mixture are a very perilous combination and there is pretty sure to be
a blazing car in a moment.
Sometimes in filling the gasoline tank it overflows and drips down.
Perhaps the driver, delayed by taking on gasoline, is in a hurry, so he
opens the “cut-out” and finds that making haste is often dangerous.
Another cause of fires comes from short-circuiting of the ignition
or lighting systems when a storage battery is used. Occasionally a
short-circuit will heat one of the wires red-hot and burn off the
insulation. Then, if there be an accumulation of grease, oil, or
gasoline, there will be trouble.
To obviate vibration, some chauffeurs pack around the battery with used
waste, which is more or less greasy. It is possible for a tool to drop
down on the battery and give off a spark, or, under vibration, a series
of sparks, sufficient to set fire to the waste. It is on record, in one
of the old-style cars, that a cushion spring wore through and dropped
down on the battery, making a spark every time the spring touched the
terminals, and eventually setting fire to the car. The remedy for all
these instances is very obvious.
Another cause of fire, which has been written about a great deal,
is static electricity, which is generated when gasoline is filtered
through chamois under certain conditions. Very many funnels have
a chamois strainer. Gasoline poured upon chamois creates static
electricity. It is all right if the funnel touches the gas tank, but
if it does not, a static spark is very likely to cross the gap and set
fire to the volatilizing gasoline. The remedy, of course, is either not
to use chamois or to see that there is a perfect connection between the
funnel and the tank.
Since one of the chief troubles is the back-firing when the car is
started, it would be well for the owner, when starting the car in
cold weather, to enrich the mixture slightly; this will prevent the
back-firing, and when the engine is well started the mixture may be
adjusted to the proper proportion. Most cars now have a means of
enriching the mixture on the dash.
It ought not to be necessary to suggest the wisdom of carrying along
one of the approved fire extinguishers, but it is a fact that very many
owners “take a chance.” The insurance companies make a reduction in the
premium when a fire extinguisher is carried, which is a pretty good
indication that they consider it a valuable accessory on the car. Some
companies insist that one be carried.
Inasmuch as fires may occur even with the most careful operator, from
causes beyond his control, such as the accidental short-circuit, or
the carelessness of others, it may be out of place to suggest that the
owner of a valuable car, or one who really cares, insure his car. Rates
are fairly reasonable, and if insurance ever is good it surely ought to
be in the case of an automobile, where several thousands of dollars are
often centered in a very small compass.