The Gasoline Motor

ors And

ble and that will be entirely consumed in the engine cylinder under ordinary conditions within about one-twentieth of a second after the formation of the spark. This rapid combustion so nearly approaches the instantaneous action of an explosion that it may be considered as such in all ordinary discu

ick was placed in the line of the intake pipe of the motor and was connected with the cylinders on the descent of the pistons on the suction stroke through the medium of the various inlet valves. In a four-cycle motor, the piston acts as a suction pump on alternate down-

opening at its upper end through which the gasoline from the feed pipe was made to pass. Fitting into the upper end of this tube, and pointed to the same angle, was a cone-shaped "needle" that could be moved in and out of the opening. If this needle was unscrewed slightly so that it did not for

proper conditions, will become vaporized almost as soon as it comes in contact with a current of air. This air current is induced by the same pump-lik

tity of air, and if this proportion is varied above one limit or below another, ignition of the charge will not occur in the cylinders. In fact, the allowable variation in the proportion of gasoline vapor to air is restricted between very n

eeds of the motor whenever that particular grade of fuel is used. By volume, about 97? per cent. of the mixture should be air and the remainder gasoline vapor, and it is the devi

rburetor. By turning this nut in one direction, the needle valve is screwed up toward the cone-shaped end of the tube and the orifice through which the gasoline may pass is thus reduced in size. This will decrease the amount of gasoline sprayed into the air passage and will consequentl

linders at each suction stroke of the piston. Throttling is used to reduce the power-and consequently the speed-developed by the motor, while a decrease

in a marked change in the composition of the charge and may make all the difference between poor and perfect running of the motor. Consequently the needle valve nut should be moved but the smal

but a slight percentage in the proportion of gasoline vapor to air, it may be well to examine, superficially, the effects of

gh intense, does not cover a sufficiently large area to ignite any charge except that composed of the proper proportion of gasoline vapor and air. If there is too much gasoline vapor, making a "rich" mixture, there will not be sufficient air in the charge to support the entire combustion of the gas, and the

e slow-burning properties of the mixture and the resulting fact that a large portion of the cylinder walls uncovered by the pistons will be exposed to the flame. In some inst

ing and to note any resulting improvement in the regularity of the explosions. It may sometimes be difficult to distinguish between the symptoms of a rich and a weak mixt

rmed at the plug. Even when ignition does take place, the resulting power impulse will be weak because of the comparatively small amount of pressure-producing gas in the mixture. The explosions may occur regularly for a wh

ere the charge too rich in gasoline vapor. Consequently the needle valve should be closed as much as is consistent with

tricted for slow speeds of the motor, and it was consequently necessary, on the old, non-automatic vaporizers, to increase the gasoline supply whenever the revolutions of the motor were to be reduced. The modern carburetor is sufficiently automatic in its action to provide the proper mix

set, such regulation should be made when the motor is well throttled, for if an ample gasoline supply is obtained at low speeds, the mixture will certainly be sufficiently rich at increased revolut

ry air opening" which serves to furnish the additional air necessary for the mixture at high speeds of the motor. The fixed opening, being restricted in size, cannot admit the increased quantity of air demanded by the higher speeds of the motor. The a

ccessive opening of different valves. Some carburetors are provided with an adjustment by means of which the "delicacy," or ease of opening, of the auxiliary air valve may be regulated. This may be done by means of a nu

the throttle should be opened and the further adjustment of the carburetor for high speeds of the motor should then be made through the auxiliary air valve. In other words, the needle valv

ce. But the suction of the motor generally increases the gasoline flow beyond the demands of the cylinders at high speeds, and it is for this reason that the automatic auxiliary air supply is provided to furnish the additional air required to support combustion. In fact, at heavy loads, when the total amount of gasoline consumed must be grea

ch charge to differ in the proportion of gasoline vapor to air, and it is hardly probable that the motor could be run at all under such conditions. In order that the pistons may suck the gasoline from a level that does not vary with the amount of fuel

oat rises and closes the valve controlling the flow of fuel. As the gasoline is sucked through the needle valve from the float chamber, the float in the latter lowers, and the fuel is again admitted by the

mber and determining at what point the flow of gasoline shall be cut off by the automatic valve. The float is supposedly properly regulated when the carburetor leaves the factory, but the stem may become bent or the carburetor m

a rich mixture which will ultimately prevent the proper operation of the motor. Turning down the gasoline supply at the needle valve will not remedy this, for the fuel will reach

. This will serve to evaporate the excess gasoline in the float chamber and reduce the level to the point at which it will not overflow. The exact number of turns and fractions of

speeds of the motor-even though the needle valve should be opened wide. The obvious remedy for such a condition is to raise the float until the gasoline will be maintained at the p

d. The first condition may be caused by a piece of dirt or other foreign matter that may have become lodged on the valve seat and prevented the valve from closing when the gasoline

turned off. The offending foreign matter will generally be carried with the gasoline as the latter is drained, and the valve in the feed pipe m

pipe joins the carburetor. If there appears to be an ample flow through this pipe when the main valve is opened, it is probable that the stoppage has occurred in the strainer. If the flow through the main feed pipe is not free, however, it is possible that the vent hole in the filler cap on the tank has become stopped or

t can be depressed so that the gasoline chamber will be filled rapidly to a point above its normal level. This is useful in starting, as the desired rich mixture is quickly obtained without an undue amount of cranking. If the carburetor flushes easily, it is evident that there is no serious

easily than will one of a lower degree of specific gravity. Also, every motorist has had impressed upon him the fact that heat aids in the vaporization of gasoline. If we try to start a motor

mber. This jacket is connected with the cooling system of the motor, and the hot water surrounding the chamber so warms the interior that vaporization is greatly fa

ation of the fuel. Some carburetors are provided with both jacket systems, while others have neither, but whatever design is installed, the best results will be obtained if cold air is used after the motor is once started. Cold air is

r than 64°-and he is sometimes lucky to obtain fuel of that specific gravity. A hydrometer, or specific gravity tester, is a convenient instrument for the average motorist to own, and with it he may tell exactly what grade of fuel he is paying for. The Baumè scale, by which all gasoline i

all adjustments and connections seem to be in perfect condition. Water is much heavier than gasoline and has no affinity for it, and consequently, as it sinks to the bottom

es in the bottom of the cup. If the contents of the cup are poured over a flat surface so that the liquid may be allowed to spread, the gasoline will be seen to cover a large surface and evaporate quickly, while the water will seem to remain i

orm added to the fuel will form a more volatile and consequently more powerful mixture, but unless the greatest care is taken, the motor is liable to be completely ruined by such a procedure

ject. The cap of the tank should never be taken off when the air is filled with particles of dust that are liable to find their way into the fuel, and care should be taken to see that no pieces of the rubber or leather washer or packing