How do I test it? I have an 81 F-100, I-6 with the infamous YFA 1 bbl carb. It doesn't seem to work. I traced the wire back to the alt stator connection and it is fine, took my multimeter to it. needless to say, there is no power to that wire unless the alt is moving, so how does the choke activate if there is no power to it? I cannot find any type of troubleshooting info in any of the Chilton's or Hayne's manuals. I can set it by hand, and it does release as it warms up, there doesn't seem to be any binding anywhere. Maybe I should just pony up for a Clifford intake and 4 bbl

 

The choke is only supposed to have power while the motor is running. You said you're getting power to it when the alt. is spinning, and the choke opens as the motor warms up. Sounds fine to me.

 

I guess what I'm trying to ask is, the choke should close with no power applied? If it doesn't close by itself, first thing in the morning, when it's cold outside, what is it that I check for?


I'm making an assumption that as it warms up, and the choke plate opens, that in theory, the choke is OK. But, the choke plate will not close, this is my problem.

 

The choke will cool down with no power supplied (and no hot air on some setups), but it won't close until you pump the gas pedal. That's what "loading the choke" does; before you start your truck in the morning after it has sat all night, you hit the gas once. That frees the fast idle linkage, and the tension in the cooled-down choke spring snaps the choke plate shut.

Here's the breakdown: in the morning, before you start the truck, you tap the gas and the choke snaps shut. As the engine warms up, the choke plate slowly opens. While the engine runs, constant power (and hot air, on some setups) keeps the choke spring hot and the choke plate open. When you shut the engine off, the choke spring cools, and if it's long enough (say, overnight), it tightens back up enough to want to shut the choke plate. But you have to "load the choke" again to let it snap shut.

Now, if your choke still won't snap shut even after you hit the gas once in the morning, there are a few possible explanations. Your choke could be set over-lean, the spring could be worn out, or there could be binding fast idle linkage that won't let the choke close.

 

OK, that makes sense. Thanks for the info.