I pressed accelator once before starting and choke plate didn’t move. I think it only opens and stays like that. When i do manually close it, it won’t close all the way and plus it doesn’t open or close smoothly. Carburetor is the first fix and move on from there. Thanks again for replies.
Take the cover off the thermal choke pull-off to check if the spring is broken.
https://www.rockauto.com/en/moreinfo.php?pk=935001&cc=1121678&jsn=478
Tester
I’m betting you fixed it.
Here’s 3 things I check on my Ford truck’s carb when this symptom develops.
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When the engine is cold, engine not running, press on the gas pedal then let it up, the choke plate should close almost completely. Now start the engine, with it idling the choke plate should be slightly cocked open, but not much. Then as the engine warms up the choke plate should slowly open a little more until about 5 minutes of idling it should be fully open. If anything doesn’t match up, then there’s a problem with the choke system. On time on my truck I had a problem where the screw that held the choke plate to its actuator rod was about to fall off, so the rod was rotating ok to the temperature changes, but the choke plate wasn’t, staying in the open position all the time. Tightening that screw fixed a similar symptom to what you are experiencing.
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Engine off, open the choke plate manually (if engine is cold, otherwise it should already be open), and look with that same view you got in post 9, direct down from the top. Now have a helper press on the gas pedal. You should see an easily noticeable squirt of gas come out in the venturi area (where those circular objects are located in the air stream) . If you don’t see that, there may be a problem with the accelerator pump.
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I’ve had problems when the engine hasn’t been used in several days, or a week say, where the carb bowl fuel level gets low, and that can cause a hard or impossible to start. Sometimes the problem is the inlet valve is stuck closed and just needs a jiggle to free it up. Take a peek under the cover at the level in the fuel bowl.
I agree.
And since it doesn’t close with the choke linkage reconnected, you may want to check the bimetalic spring (the temp sensor) that causes it to close. I believe they still had these in '86.
There’ll also be a high-idle cam involved in the system that operates the choke. It keeps the throttle plate open to a higher-than-normal idle speed when the engine is cold, and if it’s gummed up or too badly warn it can hang up and might be the reason the choke linkage became disconnected. It needs to operate freely in response to the temperature sensor (bimetallic spring).
All the Fords with Autolite 4V carbs I have worked on the IAC was a screw on the mechanical linkage.
I did get it to start up right away. The bimetallic spring does close the choke plate but not entirely. I have been watching a lot of videos on carb ajustments and carb rebuilds. I also learned three pumps on the accelerator, before start, works very well. The truck still dies after start up but atleast I have progressed to a 3 second start.The same 4 barrel carb rebuilt is about $520. It is really tempting to start with a clean carb, that has original factory settings
On a cold engine and after flooring the throttle once (or more), the choke should be completely shut. Have you tried adjusting the bimetal housing so this happens? After starting, punch the throttle once to reset the choke and idle.
My Ford truck had been running fine for several years, when all of a sudden one day it would barely idle at all. Nearly impossible to drive it ran so poorly. After discounting other possible causes, and noticing the air filter hadn’t been replaced for a long time and had gotten quite filthy, I bit the bullet and rebuilt the carb figuring dirt getting past the air filter had clogged it up. The rebuild chore was a bit of a struggle, but once the niggles and adjustments were worked out, the results were quite spectacular. Smooth running. No idling or performance problems at all.
If you don’t want to do the carb rebuild yourself, if it is the original OEM carb for your engine, suggest you get your local fuel system repair shop to rebuild it for you. Or you can mail your carb to carb repair shops that rebuild them, one is called “The Carb Shop”, in LA area I think. You don’t want to lose your original OEM carb if at all possible. If you do decide to buy a new carb, don’t turn the old one in. Just eat the core charge and hang on to your original carb, b/c most likely you’ll be happy you did at some point.
Folks here will guide you through the rebuild process too, if you want to do it that way.
The OE carburetor appears to have been a Holley 4bbl with a vacuum secondary. While it is somewhat basic it is very busy and I wouldn’t recommend it as a first for a DIYer. But if you’re up to the challenge I suggest setting up a well lighted work table with a clean sheet on it. And while there are accurate diagrams with rebuild kits they can be confusing due to mixing components from various similar models. A model specific diagram and instructions would be helpful. Good luck
The carburetor doesn’t need rebuilding, because OP complains of a starting issue not an operation issue.
This is a choke issue,
The choke works like this.
When you step on the accelerator pedal, the thermal choke spring causes the choke plate to close completely while at the same time rotates high fast idle cam to the proper position.
When the engine is started, the primary choke pull-off slightly opens the choke plate to allow some air into the engine while at fast idle.
If you step on the accelerator while the engine is at fast idle, the secondary choke pull-off opens the choke plate relative to throttle position so the engine doesn’t stall from flooding.
While all this is happening, the thermal choke spring is heating up until it fully pulls open the choke.
Tester
While it does seem certain that the choke stat is the #1 problem this thread has wound around significantly and honestly it’s difficult to guess that a 30 year old Holley 4bbl doesn’t have a blown power valve and a leaking accelerator pump. But if you’re correct the choke is often pop riveted on and requires drilling out to remove and careful installation of self tapping screws to replace it.
Up there somewhere the OP mentioned that the choke linkage was disconnected which throws a lot of question marks up for me.
But replacing the choke stat may be all that is needed and is certainly worth taking care of first.
If there a simple way the OP could prove the choke is the only problem? If I had what I believed to be a choke-only problem on my truck, I’d figure out a way to hold the choke completely open, prime the carb with a squirt of starter fluid down the throat, start and let the engine warm up while diddling the accel pedal to keep it running until the engine warms up. If it runs and idles fine at that point, wouldn’t that prove the choke is the only problem?
I would start with removing the choke cover and cleaning all of the linkage with carburetor cleaner making sure the choke linkage operates freely, then reinstall the choke cover. The choke cover may not be “keyed” so be sure to mark it’s rotational orientation on the housing so it can be installed with the same tension as before.
Years ago almost any parts store had manual choke kits. Maybe one could be made to work that way.
I don’t know if part’s stores carry them any more but you can buy a hydraulic cable at some part’s store’s or tractor supply’store’s or use a lawn mower cable & make your own chock cable.
The O.E. choke spring allows the choke pull-off to open the choke plate a calibrated amount, this prevents spark plug fouling and reduces fuel contamination in the oil. I would first clean the dirty choke and carburetor parts.
I saw such a kit at an auto parts store just a few weeks ago, as a matter of fact
IMHO this is just a way to try to compensate for the problems, but the problems will remain.
At this juncture I’m inclined to agree with Rod. I can’t imagine that the elastomers aren’t deteriorated. The choke linkage having been disconnected suggests too that perhaps someone was trying to struggle through life with a carb that had problems… and this was a solution they tried. Logical? No. But, than, one never knows…
This original complaint points to a float bowl that isn’t holding its gas. Chances are that a rebuild with new floats included would put this back in order as well. It’s highly possible that the float is bad, the inlet valve and seat are bad, and such as these.
I would prefer opening the hood and priming the carburetor rather than fighting the aggravation of dealing with an after market manual choke when the engine fails to start due to the cold. I have installed a few and recall refunding the unhappy customers. Manual chokes work on carburetors designed for them but retrofitting them to carburetors with automatic chokes is a real pain that rarely ends well.