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Hello there,
My 66 289 2bbl has become hard to start. Tried starter fluid but no help. Once it does start, it will idle rough for a minute and then just shut down. In looking at the carb, I noticed the plate is always open and has a range of just about an inch. (See pic, that is as closed as it can go). Wondering if it’s a choke issue. It’s a autoline c825 carb. I’ve never worked on carbs so have no idea what I’m doing. Please dumb down any answers to my level. Also-and I have no idea if this is related- it started this sh*t just after I put seafoam in the tank. Thanks! 26107371-B289-445C-8206-440EB3CB0402.jpeg D830DCA5-2D56-4E52-B652-198262C841A7.jpeg F948C633-9EEE-4287-BBB0-4B19A5087AD5.jpeg
 

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The choke doesn't appear to be working correctly. When cold if you cycle the accelerator it should close to about a 1/8” gap. It is also possible the sea foam loosened crud, rust , bunk in your fuel tank or Fuel lines which have now travelled to the carb plugging up the fuel filter or various small orifices in the carb.

go to Mikes Carbs and buy a good rebuilt kit. Soak the carb body for an hour in carb cleaner, and rebuilt it following the instructions that come with the kit and the shop manual.
 
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I'd start by replacing the fuel filter there just in case it got clogged up with whatever the Seafoam loosened up.

The choke is supposed to activate when you pump the gas pedal, so in order to close it further to make sure it's not jammed you'll need to pull the gas pedal rod at the carb at the same time you're playing with the choke. So pull the gas pedal rod back and then you should be able to move the choke plate around freely.
 

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So, what you have there is your basic Motorcraft 2150 carburetor. It's not a bad unit so let's start with the basics...

First, the choke system. The choke thermostat appears to be properly indexed in the photos, with the notch on the black plastic cap on the center of the scale. What I can't see from the photos is if the hot air tube from the exhaust manifold to the choke housing is there and properly connected. The fresh air side of the choke appears to be non-existent as the nipple to the carburetor air horn, behind the choke assembly, has nothing connected to it. These connections are necessary for the choke to operate properly. The heater hose clamp to the outside of the choke is only a small part of that system.

On a cold engine, when initially opening the throttle once, fully, the choke should snap to the shut position and the throttle placed on the fast idle cam "step". After cranking and when the engine fires and starts, the choke unloader...that piston-type thingy on the back of the carburetor...will pull the choke plate open slightly to allow air to enter so as not to flood the engine. As heat from the exhaust manifold makes its way to the choke housing, the bi-metal spring inside the choke cap will unwind and gradually open the choke over the course of a couple minutes until wide open.

If this isn't happening then you need to determine why. First, and foremost, the choke linkages need to be free. Block the throttle open at least halfway and you should be able to run the choke plate from fully open to fully closed. Lubricate the choke linkages and pivot points and move the choke back and forth until free and very easy to move. I'd start with some Liquid Wrench, initially, then when everything is free I'd clean up with some Carb and Choke cleaner spray and if you have a "dry lubricant" such as a graphite spray I'd use that on the linkages.

Once everything is free, if the choke does not snap closed on a cold engine after the throttle is opened then it's time to remove the choke thermostatic cap and examine the spring and the "tang" from the choke linkage that fits into it. Some choke springs have a slot and others are wound in a loop at the end. In either case, the "tang" needs to fit in the center so the spring can not only close but also open the choke. After fitting the "tang" in place, with the throttle blocked open, you'd rotate the choke thermostat until the choke plate closes and look at the relationship between the notch in the cap and the "index" marks on the choke housing. If you've had to rotate the cap more than a notch or two past the center index mark then the choke thermostat may be worn out and needing replacement. The typical "adjustment" varies from right on the center index mark to 1 or 2 "rich" and this usually results in the choke plate being "firmly" shut.

The next step is the "choke unloader" adjustment. Grab a 1/8" drill bit, rod or dowel. Push down on the choke unloader until the diaphragm is seated and use the drill bit, etc., to measure the distance between the choke plate and the air horn wall. On the underside of the choke unloader is an adjusting screw. Turn it to obtain a "loose fit" of the drill bit or dowel.

Once all this is done, start the engine and adjust the fast idle speed to approximately 1,600 rpm. These settings I have mentioned are all pretty much "generic" as the 2150 wasn't installed on cars until 1970 or later.

A couple other notes.... There should be an inlet filter screwed into the front of your carburetor. I see none. Some of the symptoms you describe could be attributable to a collection of debris in the float bowl of the carburetor that are plugging orifices/passages.

Also, these comments assume that your IGNITION system is functioning properly. A weak spark can also cause symptoms as described.

Good luck.
 

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That cannot possibly be the correct carburetor. The 2150 was introduced years after 1966. It seems to be marked "2CBA", and certainly is too small for a 66 289, with a 1.08 venturi. The 66 289 2V should have a 1.14 venturi.

I would suggest adjusting the choke for proper operation, and begin searching for a correct carburetor for your 1966 289.

You seem to have the correct throttle spring bracket, but it is not being used. You have two generic springs, mounted incorrectly.
 

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That cannot possibly be the correct carburetor. The 2150 was introduced years after 1966. It seems to be marked "2CBA", and certainly is too small for a 66 289, with a 1.08 venturi. The 66 289 2V should have a 1.14 venturi.

I would suggest adjusting the choke for proper operation, and begin searching for a correct carburetor for your 1966 289.

You seem to have the correct throttle spring bracket, but it is not being used. You have two generic springs, mounted incorrectly.
I agree with searching for the "correct carb". It should be noted, though, that the Motorcraft 2150 was produced in only two venturi sizes... 1.08" and 1.21" with the 1.08" version used in applications up to and including 302 cubic inch and the 1.21" version used in 351 and 400 cubic inch engines. While being rather "limited" in airflow to about 287 cfm, the 1.08" version can support a 289 with stock heads up to around 4,200 rpm... after that torque would decrease rapidly. If you're cruising and not in the habit of "puttin' the pedal to da metal" you'd probably find it to have decent throttle response and fuel mileage.
 

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I agree with searching for the "correct carb". It should be noted, though, that the Motorcraft 2150 was produced in only two venturi sizes... 1.08" and 1.21" with the 1.08" version used in applications up to and including 302 cubic inch and the 1.21" version used in 351 and 400 cubic inch engines. While being rather "limited" in airflow to about 287 cfm, the 1.08" version can support a 289 with stock heads up to around 4,200 rpm... after that torque would decrease rapidly. If you're cruising and not in the habit of "puttin' the pedal to da metal" you'd probably find it to have decent throttle response and fuel mileage.
Thanks to all. Just a bit more info. The carb that’s pictured is the autofine c825 I had put on 3 yrs ago. I did have it tuned by mustang barn outside Philly and assumed setup was fine. The car has been sitting (inside though) for 3 years while I put everything back together with just a couple of hundred miles in that time (although running great when I took it out). Question: I have the original 2100with 1.08 Venturi and a rebuild kit. Do you think it’s a better idea to stick that one back in (after rebuild)?
 

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Try a new fuel filter and looking inside the fuel bowl for dirt...a little clean-up may go a long way... otherwise for stock driving, use the stock carb.
 

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What fuel did you have in it. If it sat for 3 years (or more than an few months) with ethanol in it, the carb needs a rebuild. Ethanol begins breaking down as soon as it’s in the car and creates sludge that clogs all the little orifices in the carb.
 
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