Classic cars repair

Old Carburetors

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This carburetor is a plain-tube, single-stage type of carburetor.
It is designed principally for small engines and is made with a 1" outlet.
Fig. 8. Sectional view of Ball & Ball S-1 carburetor used on Chrysler "50"

This carburetor differs from all other Ball & Ball carburetors in that the second stage and the step-up features are eliminated and the primary stage as used on the SV-26 and SV-33 in a slightly modified form is utilized.
The construction and principle of operation is shown in Fig. 8 and is explained as follows:
Gasoline is fed to the float chamber through the gas inlet, thence through the strainer, through the float needle valve, which is actuated by the metal ball float.
Idling on low speed or almost closed throttle position: The gasoline passes through the main metering screw (B), into the idling fuel jet (Ll) into the idling mixing chamber (L2) where it is mixed with air from passage (L3) in the main throat, thence up the idling tube (LI) to the idling discharge (L5) at the throttle.
High speed: This pertains to throttle opening corresponding to speeds on a level road of over andabove approximately eight miles per hour. The gasoline passes through the main metering screw (B) through a horizontal channel (Z) to the well (D) surrounding the main nozzle (Cl), thence through a series of holes into the nozzle, thence into the throat past throttle into intake manifold and combustion chamber.
The principle of action of this nozzle (Cl) is explained as follows: This nozzle does not discharge at almost closed throttle position but comes into action as the throttle is opened from this position at which time the idling discharge (L5) ceases to function, and owing to this fact it is important that the idling adjustment be properly set, otherwise the idling of carburetor may stop functioning too soon thereby causing too lean a mixture and probable missing of explosion.
The amount of gasoline that goes into the nozzle (Cl) depends upon the level of gasoline in the well (D), and this in turn varies with the speed and throttle opening, being lower down at the higher speed. The nozzle holes that are above the gasoline level feed air which enters through an outside air Bleed (C2).
When starting, the air choke blade (AC) is fully closed by the pull button on the instrument board. This causes an increase of vacuum on fuel nozzle (Cl) and an additional increase of vacuum is obtained mechanically by the closing of the nozzle tip vent. This vent is fitted with a self-centering valve (C3), and this valve opens and closes in conjunction with the air choke valve (AC), being connected mechanically with it.
There is only one adjustment which is the idling adjustment, which regulates the size opening of the air intake (L3) into the idling mixing chamber (L2) by means of a knurled thumb screw (L). Turning clockwise enriches the mixture and counter-clockwise leans the mixture.
Adjust for idling with the throttle blade set for a minimum road speed of four or five miles per hour and make the mixture as rich as possible without rolling with the spark retarded.
Float Level
The fuel level in the S-1 is one half-inch below the upper face of the lower body. This may be checked by removing the nozzle vent (C2). Gasoline should lie about one-half inch from the top of the hole. The level may he changed by putting gaskets of different thicknesses under the float valve seat.

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Carburetor Manuals: Ball & Ball