Hey guys,
I just installed a manual choke on my 1983 F150 4.9, with the Carter YFA 1bbl carburetor.
I thought it would be cool, fun, and a little unique, and I was tired of having to adjust the auto choke for something that seemed so simple.

It worked great for a while. Then, the day after the install, I was checking under the hood with the air cleaner off to make sure everything was still working right.
The cable pulled the choke closed with no trouble, but I found that it would get stuck most of the way shut, and the cable would just bunch up rather than pushing it back open.
I disconnected the cable and worked the choke flap with my fingers. It still kept getting stuck at the same spot and required force to "snap" it open. I jiggled some parts of the linkage and somehow got it to free itself up.
It was fine for a few hours, from that point on, but then it bound up again after I drove around and parked the truck.

I recognize that the manual choke is a custom job with liability in my own design and work, but the sticky choke issue doesn't seem like a new thing.
One of the reasons I went to manual choke in the first place was because the auto choke was failing to pull off on cold starts. This is probably because of the same problem.

There is a piston that moves up and down, connected to the choke tang. This seemed to be the culprit, but I'm not sure what it does or what to call it.

In addition to the above, my heat tube from the exhaust manifold still goes into the dummy choke housing. Is there any reason to get rid of it? If not, I'll keep it in case I ever want to go back.

Let me know if you want any pictures of my particular setup.

 

Can you get a picture of this piston thing?

Also, you need to fasten the choke cable down as good as you can along it's length. If you have a bunch of s turns in it, it will tend to bunch up rather than do it's job and move the wire inside. That springy feel you get when moving the choke **** in the cab is coming from the cable bunching up, but simply fastening the cable down will help. And try not to have any sharp turns.

 

Here is a picture from the rear of the carburetor, choke cable not installed:


Good point about the cable supports.

The cable runs thru the passenger side of the firewall. I initially had it going thru the driver's side, but it was very sloppy and interfered with the air cleaner.
I used a zip tie to tightly fasten the ribbed cable to the brake booster vacuum line near the tree. It seems to hold pretty well.
The cable moved smooth as butter for the first times I tried it, after putting it on the passenger side. It wasn't until I got back from the test drive that it started seizing up.




Cable close-up with supports marked. Please ignore the zip tied choke cap!

Regardless of the cable's route, I think the sticky choke is its own problem.
Even with the cable disconnected, I could try and open the choke by hand and it would seize up and then pop open.
If there's a way to disconnect or remove the "choke piston", that would simplify things for me. All I need is the choke tang for my linkage.

 

That carb is set up like a Holley. The piston thing is the choke pull-off. In that choke casting should be a least one hole leading to that piston. That hole leads to engine vacuum.

In the automatic operation of the choke, most of the time it completely shuts the choke door. It's not sensitive enough to be able to partially shut the choke during different engine temperature scenarios. So the engine starts right up with the choke shut, but will soon flood out and stall if the choke door stays shut. So that is what the piston does. As the engine starts and builds vacuum, the piston will move down from the vacuum of the engine and it will crack open the choke so the engine gets a little bit of air. The official name for this piece is "choke qualifier" or "choke pull-off".

This piece should not interfere with your manual choke operation. It can actually work with it when it's working properly. It is funny, this happens to me all the time. I will have a problem with an engine or something else on the vehicle, and finally get fed up and take it off and rig something else up. 50% of the time when I do this, I run into what my actual original problem was in the first place. This piece may have been your original choke problem.

I would continue on with the manual choke, I like their simplicity myself. I am not too familiar with that particular carb, but there is probably some way to take the choke pull-off out of the picture. But it looks like you might have to partially tear the carb down to do it.

 

 

Since you just added manal control to the choke housing it could be hanging up on the fast idle cam a bit . In normal operation the fast idle cam adjusts when the throttle is depressed . If you are trying to move the choke with the throttle released you may be dragging on the fast idle cam, a good rule of thumb with these choke cap setups is to have have the throttle depressed a bit when using the manual choke True manual chokes have a different set ups for the fast idle cam that negates this issue. Do not worry about the choke pull down it will have no affect on your manual operation and is just along for the ride now..


Now to the core of the issue , your support of the cable sheath it is not close enough to the end of the cable. If you look at manual chokes the support is quite close to the end of the cable.
See below pic of a carter 1BBL with manual choke. You will have to find a way to secure the cable sheath closer to the end. This will solve your problem.

 

Thanks for pointing that out, I didn't even look at that part in his picture. The manual choke kits used to come with a small universal L bracket for that purpose. Everything you get like this that is universal always takes a bit of engineering to get it working correctly.

 

Sounds good. I drove a few places today and it seems to work great after a few adjustments I made this morning.
My kit came with a bracket. I'll see if I can mount it on the carburetor body or something, but there isn't a whole lot of real estate for space in the area.
Since my cable comes up from below the carburetor rather than the side, it's a little hard to get a bracket near it.

My fast idle cam interferes when you try to pull it fully closed -- this is actually a little bit useful because my engine prefers to only be half choked when cold starting.
I can get a perfect cold start just by pulling the choke, then pumping the gas.
If I push and hold the accelerator, I can close the choke fully and make the engine fast idle by itself.

When the choke was hanging up the other day, I kept a good eye on the fast idle linkage but it appeared to be completely free.
Still not sure why it was binding, I'll keep an eye on it. Remember this was happening even without the manual choke cable attached.

 

You are getting the idea now. Each engine seems to be a little different, somewhat like a weedeater or old lawnmower with a manual choke. Once you get the routine down it should work well. You may have to change your routine a little bit if the weather gets colder.

 

Yes, I am very pleased with it!
I've found I don't have to use the choke at all unless the engine has been sitting all night.
Even with engine temp as low as 100 degrees, I can give it one pump of gas and it will start right up with no sputtering.

At my summer job, I drove a lawn tractor with a choke, and it would usually not start unless you choked it fully, even when hot.
It's one of those things that adds character to a vehicle.