I posted over in the General Engine section and realized I may have posted in the wrong place. Now that I made a video of the problem, I'm hoping someone can help.

The choke is never setting. Something in my throttle linkage is wrong or sticky and it doesn't flip up the lever that engages the choke?

Hard to explain. Hopefully the video makes it clear?

 

There's nothing wrong with it, you adjust the choke when it's cold by (holding the throttle open) and then rotating the choke thermostat cover until the choke plate just closes, when the choke is closed the 2-step fast idle cam should be engaged, the little piece you are flipping around is the fast idle cam, you can't set the choke with throttle closed..

 

Well, I can't get it to fast idle (and when it does, it comes off the fast idle as soon as I touch the throttle.)

I can see on the choke side that it should slowly come off the fast idle as the choke opens but this is not what it does.... Basically -- the truck is hard to start. When it does start, it runs great on the fast idle but if you touch the throttle before its warm, it dies.

Once warm it idles and runs perfectly.

 

Back out the mixture screws about 1/2 turn. Also, where is your choke voltage coming from? It should be from the alternator stator wire.

You also need to adjust the choke tighter as mentioned above.

 

When cold I can't get the choke adjustment far enough forward to close the choke -- unless I flip up that lever on the throttle side that you see towards the end of the video. And I can only get that lever to engage by pushing it with my hand. I can't get the gas-pedal/throttle linkage to engage it (only to dis-engage it.)

The entire video is shot with a cold engine that hadn't been started or had the key on in 3 days. I double-checked that there is not 12v at the automatic choke spring until the key is on.

My choke voltage is coming from a switched +12v on the fuse-box that also powers the coil on my HEI carb.

 

The choke thermostat is set too loose, loosen the screws and twist it a bit more, this will help to keep the throttle on the fast idle cam for a longer period of time.
The idle air screws are too tight also, back them out as suggested and then back them out some more until they have no effect on idle speed or quality, now turn them back in 1/2 turn at a time until the idle speed becomes to drop and stop.

 

I twisted the choke thermostat another 90 degrees and it didn't push it any further closed. I know I sound like a broken record but shouldn't the throttle linkage being "Setting" the choke??

 

It sounds like the choke spring under the black cap is not properly attached to the choke lever. Remove the choke cap and reseat the linkage to the spring.

 

The spring is properly attached. I'll try and take another video to show you guys....

 

Mine closes as tight as I want it too. I do have to hold the throttle open when adjusting which makes it easier to get the flap where I want it.

 

Again -- I can adjust it and get it closed properly, but only if I have the choke "set" (like I am flipping the linkage behind the throttle at the end of the video.) Once that lever is in the "set" (or up) position, the adjustment on the black cap works as it should.

The problem/issue is that I can't get that choke lever to "set" without using my hand.

How does your choke set?

 

Once I have it set when I want it. When ever it is cold, i just pump the throttle a couple of times to prime it. The flap closes when I push the throttle the first time.
I'm not sure why yours does not close when cold and you open the throttle.

 

The choke should snap shut when you open the throttle. If it does NOT, the choke is not adjusted properly, or it's warmed up. With the choke cooled off and the throttle open (to free the fast idle linkage), rotating the choke should open and close the choke plate. If it does NOT, either the choke tang is not grabbing the choke plate lever, or the linkage is binding.

 

Thank you. It seems like everything is adjusted/engaged on the choke -- it really seems like the linkage on the throttle side is wrong or missing a spring or something. When I adjust the choke housing, I can feel the tang putting pressure on the choke plate and I can adjust it -- but only when that lever on the right is flipped up manually. The throttle linakge doesn't appear to be interfacing correctly with that part, but I can't for the life of me figure out how it's supposed to work.

 

Can you rotate the choke cap, and watch the choke plate rotate? The choke tang needs to "hook" the tab under the cap. There are no springs, just the rotating lever on the choke housing, and a link to run up to the choke plate.