Classic cars repair

Old Carburetors

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Construction; Operation
The carburetor used on the Lincoln is the Stromberg model 0-3. The description of this carburetor and adjustments is given on pages 1244-1249. The prefix of the 3 to model 0 means that it is in size.
The electro-fog attachment is a special heating device provided to overcome the difficulty sometimes experienced in starting a cold engine. It is operated by pulling the carburetor choke control button on the instrument board, all the way out against the stop provided, and maintaining it in that position for approximately 15 seconds, causing the electrofog generator to function as follows:
Pulling the choke control (3) all the way out closes the electro-fog switch which is attached to the back of the intake manifold (1).

This switch is in the circuit between the battery and the heating or fog-producing element.
It is thermostatically controlled and automatically cuts off the current after a lapse of time which is sufficient to produce the fog for starting. It is such a sensitive device that in warm weather it automatically remains open and inoperative, due to its thermostatic principle.
The heating element is contained in a small retort at the bottom of the carburetor (10), and is surrounded by a soft incombustible substance which absorbs the gasoline to be vaporized. Gasoline is automatically supplied to the retort by the unvaporized fuel in the intake manifold which drains back into it when the engine is stopped.

When the switch is closed the gasoline contained in the retort is subjected to a temperature above the boiling point of the fuel, and in a very few seconds the carburetor manifold is filled with a foggy vapor.
The heating element is purposely overloaded to the incandescent point and then cut off thermostatically. This accomplishes in a few seconds what would ordinarily require considerable time.

The electro-fog generator operates for a period of 10 to 15 seconds, and is then automatically cut off. The first five seconds are required to bring the fuel to the fog point and the remainder of the period to produce sufficient fog for several explosions.

Operation: When the carburetor choke control button on the instrument board (connected with 3) is pulled out the first part of the movement of the control closes the carburetor choke valve (7) shutting off nearly all air from entering the carburetor.

By pulling the choke control all the way out to the fixed stop position, one of the members of the electro-fog switch (2) is pushed toward and engages the thermostatic member of the switch. The circuit is thus closed between the battery and the heating element, which is grounded in the retort.
Caution: The electro-fog generator should not be operated when the retort containing the heating element is dry, as this will cause the heating element to burn out. This condition will be brought about by demonstrating the device without turning the engine over or from the vacuum tank being dry. No harm will result from operating the generator several times in succession if the engine is cranked at each trial, as sufficient fuel will drain back into the retort to replenish the supply.

The thermostatic member of the electro-fog switch is composed of two strips of metal (enclosed in electro-fog switch box) having different expansionratios. Closing the circuit causes these strips to become hot and because one metal expands more rapidly than the other the strip bends and after 10 to 15 seconds will break the circuit.

The spring strip is operated by a plunger (2) which is actuated by the lever (4) which- is operated from the carburetor choke control button connected with (3).
The wire in (9) connects the heating element (10, on opposite side of carburetor) with the spring strip, and the wire in (8) connects the thermostatic member of the switch with the battery at the starter generator terminal.
Fig. 1. Side view of Stromberg Model 0-3 Carburetor as used on the Lincoln 8 with the electro-fog generator and air cleaner attached.

The air cleaner is of the centrifugal type, placed as shown at the main air intake opening of the carburetor.
To avoid any possibility of the carburetor air supply being restricted at high speeds with wide open throttle, an automatic valve (15) is provided in the bottom of the air cleaner, which opens when the suction in the pipe becomes strong enough to lift the valve, the correct weight of which keeps the valve seated under all ordinary conditions.

Names of parts of Lincoln-Stromberg Carburetor: (1) intake manifold (it is cored for water outlet from cylinder jackets) ; (2) plunger which closes the circuit between the two metal strips in electro-fog switch box; (3) carburetor choke and heater control rod; connects with choke button on instrument board; (4) actuating lever; (5) heater switch connecting link; (6) carburetor choke rod; (7) carburetor choke valve lever; (8) wire assembly; switch to battery (connected at starter terminal); (9) wire assembly; switch to heater unit; (10) the heating unit is connected with (9) on the opposite side; (11) throttle valve on opposite side is connected to this throttle rod; (12) economizer needle also connected to throttle lever; (13) carburetor air intake; (14) air cleaner; (15) automatic air valve at bottom of air cleaner; (16) accelerating well drain plug; (17) float chamber drain plug; (18) fuel inlet; connects with vacuum tank; (19) float chamber fuel level plug (see page 1245 for adjusting gasoline float level); (20) idling adjustment screw.

Air cleaner lubrication: Lubrication of the shaft on which the cleaner mechanism revolves is taken care of by oil, fed from the oil-soaked felt around the shaft and at the top of the rotor. By referring to the illustration it will be seen that the weight of the cleaner rotor is supported on a single ball bearing, which results in a minimum of friction, and requires the least lubrication.

Editors Note: Rotor in these old manuals refers to a whole variety of rotating parts; this is even more true in modern days when Ebay, for example, has more than 11,000 auctions for various kinds of rotors. That includes brake rotors. Ignition rotors, motorcycle rotors and many others.

The end play of the rotor is adjusted by loosening the three screws which attach the outer shell, and revolving this shell slightly. The holes in the shell through which the screws pass are slotted and at a slight angle, so revolving the shell also raises or lowers it slightly. Do not adjust the end play too closely, as the rotor must revolve very freely with no tendency to bind.

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