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Still another method which renders the wheel easy to remove is illustrated in Fig. 58. This consists of a tapered shaft with shoulder A, which is threaded and provided with a nut B. The wheel is forced up on the taper and shoulder as in the ordinary tapered shaft and the nut B is then set up against it. When the wheel is to be taken off the forward lock-nut C is removed, and by turning the rear nut B against the wheel the latter is easily forced off the shaft. This idea is original with the author and has been employed on several motors with great success. Even with a straight shaft and key the rear nut will force the wheel from the shaft unless very badly corroded.
MOTOR ACCESSORIES-VAPORIZERS-CARBURETORS— COOLING SYS
TEMS-FANS AND PUMPS-CIRCULATING DEVICES-LUBRICA-
All attachments and parts of a gasolene engine, not actually a part of the motor itself, may be classed under the general head of Accessories, for while these various devices may outnumber the parts of the motor and the latter may be incapable of operating without them, yet they are seldom manufactured by the motor manufacturers and often are of equal importance and of greater value than the bare engine. In fact a motor without accessories is no better than so much old metal, as far as use is concerned. Nevertheless, many owners or operators of gasolene motors who are very careful to purchase or use the best motor that money can buy are very careless or indifferent where the attachments or accessories are concerned. In reality most failures of gasolene motors to give satisfaction are due to faulty or poorly constructed or obsolete accessories. The best motor in the world will not operate properly with poor ignition or poor vaporizing devices, whereas a poor motor will often work fairly well if furnished high-class ignition and fuel-mixing apparatus. Every gasolene motor must be supplied with some sort of device for furnishing the explosive gas and for so combining the air and fuel as to
form the proper mixture or "gas” to give the greatest possible explosive force without waste of fuel.
Such devices are known as mixers, carburetors, or vaporizers, and they may be roughly divided into three groups: Vaporizers, Float-feed Carburetors, and Mechanically operated Mixers. Gasolene, benzine, kerosene, alcohol, or any other liquid fuel must be vaporized or transformed into an explosive gas by mixing with air
before it can be utilized as a fuel for internal-combustion engines. The function of either mixers, carburetors, or vaporizers is to create a mixture of gasolene or other fuel with the air in such proportions as to give the highest efficiency. Vaporizers as a rule are cheaper and simpler than carburetors and are not nearly as satisfactory. A common form is illustrated in Fig. 59. In this cut A
represents the inlet to motor; B, the gasolene supply pipe or inlet; C, the air intake; D, the needle valve; and E, the check valve. The gasolene flows through the opening of the needle valve D and the amount admitted to the motor is varied by screwing the valve up or down. While the check valve E is held on its seat by the spring F, the opening of the needle valve is closed and no gasolene flows through. As soon as the motor commences to operate the suction through the inlet A draws air through the inlet C and this suction raises the check valve from its seat, allowing a small jet of gasolene to run into the vaporizer. This gasolene is mixed with the air as it rushes through from C to A and passes into the motor in the form of a vapor or fine spray. By varying the adjustment of the needle valve D and the lift of the check valve E, the proportion of gasolene to air can be varied to suit the speed or condition of the motor. In theory this system is excellent, but in actual operation it often proves faulty.
The best form of fuel mixer is undoubtedly the floatfeed carburetor. A number of makes of these carburetors are on the market and each has its own good points and advantages. The operation of all is very similar and if one is thoroughly understood the others are easily mastered. A form in common use and which invariably gives most satisfactory results is known as the “Schebler.” This carburetor is made in several forms and types, varying in the arrangement of air and gasolene supply and regulating devices, but the simpler form known as ‘Model D” is as satisfactory for general use as any and is far easier to understand than the more complicated
models. This carburetor is illustrated in Fig. 60, in which R represents the inlet to motor; G, the gasolene pipe inlet; A-C, the air intake; D-E, the needle valve; 0, the automatic air valve; F, the float; and I, the float valve. The flow of gasolene fills the float chamber B until the float F rises upward and shuts off the supply
by the float valve H. As long as the motor is inactive this level remains constant and no gasolene passes into the motor. As soon as the piston moves on the suction, or intake, stroke a current of air is drawn through C and across the opening of the needle valve towards the motor