Many troubles which prevent smooth running at idle may cause stalling. The list includes almost everything that may cause hard starting or missing. Some of the more common causes are:
If carburetor is equipped with a fast idle cam, which increases engine speed when the choke is in operation during the warm-up period, the engine may stall if the fast idle device fails to open the throttle due to sticking or need for adjustment.
On some cars equipped with a fluid coupling or torque converter, if the throttle is closed quickly the engine stalls. To avoid this trouble, most cars have a device which retards the speed of the throttle closing; this is called a dashpot and is usually mounted on the carburetor. It consists of a piston or diaphragm and a spring-closed check valve. If the linkage is out of adjustment or the check valve leaks, the engine will stall.
If the engine quits smoothly when car is in operation, the trouble is often caused by sudden lack of fuel due to: