DeSoto Carburetors for old Desoto's : DESOTO MODEL S8 1941 Previous | Home | Next

Page 3
The leather seal on piston (3, Fick. i) co,lirols t,,e retarding action. Should this seal become worn, cracked or dry, the action will be upset. A good seal is necessary for the control to function properly.

DASH-POT (Second Type) Figure 2
The solenoid controlled dash-pot functions as follows: When the car speed is below 8 m.p.h., in low speed range, and 15 m.p.h., in high speed range, the transmission governor points close, which energizes the dash-pot solenoid (3), through electrical terminals (9), raises the solenoid core (4), which permits the ball (7) to reach upper seat when piston (I) moves down. When the ball (7) is on its seat, fuel is discharged only through the restricted opening (6), causing the throttle to close slowly.
When the car speed is above 8 m.p.h., in low speed range, or 15 m.p.h., in high speed range, the trans-mission governor points are open, the solenoid is not energized and the solenoid core (4) _is held down by the spring (8) which prevents the ball (7) from seating. This permits free flow of fuel from the cylinder through fuel passage (2) and fuel openings (5), which permits dash-pot plunger to operate freely without causing throttle to close slowly. The slow closing of throttle is not desirable above speeds given, but is necessary at low speeds due to the action of fluid drive.
NOTE
In replacing a carbureter having the dash-pot (first type) with one having the dash-pot (second type) as described above, the electrical connections should be made as follows:
1. Connect either one of the solenoid terminals (9) Figure 2, with the terminal on the kick-down limit switch on the carbureter (marked 6 on cut of switch [Figure 3]).

2. Connect the other solenoid terminal (9) Figure 2, to the point marked SF (solenoid feed) on the relay, Chrysler part No. 868606, situated at the right of the voltage regulator. The relay terminal marked SF already carries 2 wires and will then have 3 wires connected.
THE KICK-DOWN SWITCH—USED WITH SIMPLI-
MATIC TRANSMISSION (Figure 3)
The kick-down switch (Fig. 3) functions as follows: Plunger (5) is moved inward when the accelerator pedal is depressed. When the pedal is fully depressed, this plunger makes contact with contact arm (3) and moves it against a contact which energizes the solenoid circuit, permitting the transmission to function. Contact arm (3, Fig. 3) is attached to piston (2) which moves up and down dependent upon the velocity of air at the carbureter venturi, and consequently its position varies according to engine speed. At an engine speed that corresponds to 50 to 55 miles per hour in high gear, the piston (2) will be moved up so that the contact (4, Fig. 3) attached to it will not be opposite plunger (5). Consequently, if the acceleratorpedal is depressed to the floor board at speeds of 50 to 55 or over, there will be no contact made and, therefore, no kick down of the transmission. At speeds below this limit, contact will be made and gear changing effected. There are no adjustments necessary and proper functioning depends upon freedom of the parts to move and operate.
If it becomes necessary to replace the switch piston spring (large spring that fits into piston) do not remove the washers in piston, if any. If piston assembly is replaced, use new spring and install both without washers. Do not use washers with new piston assembly and spring.
Figure 3
Figure 2