The choke plate should be fully closed on a cold start up. Each system has what they call a "choke pull-off" or "choke qualifier"(they have another name for it but it's not coming to me right now).

When cold the choke door goes fully shut. But of course like you said it won't run very long like this. So each system has some sort of vacuum mechanism that when the engine starts and vacuum builds, it cracks the choke door open.

Some have a external diaphragm unit with a lever, and the Holley's have a little piston made into the housing where the round black piece bolts to.

See what I mean? These things are involved. And guess what? This choke-pull off has a spec. You have to take your finger or some other method and pull the choke pull-off back, and then measure the crack at the choke. If the crack is not large enough, the engine can flood out or burn rich. If the crack is too wide the engine will start up and then instantly stall as the choke door opens too much. On most of the external units, you have to take pliers and bend the rod to adjust it.

 

It's still a gasoline engine, no different than starting a mini bike or lawn mower or chain saw. The industry has come up with a method (automatic choke) to put into place so people don't have to futz with this stuff on their own... which is great when it works, not so great when things go wrong.

 

You can say that again!


That was some GREAT reading and a very detailed explanation on why carbureted vehicles need a choke and what it does.

Thanks!


And this quote from the above article:

This statement is so true. I was pleasantly surprised when I finally got my own carburetor and choke set up and tuned correctly. Other than pressing the gas one time in the morning to set the choke, my truck starts immediately and runs just as good as any modern EFI vehicle.

 

Will this help?


https://www.ford-trucks.com/forums/1...ent-101-a.html

 

The best carb I ever had, was on the 351C, in my E-300.
I could reach through the window and start it without ever touching the gas pedal.
After rebuilding the engine and carb, it never worked that way again.