Hello, I have a 83 F250 4X4 auto extended cab pu. It has the 2150A carb on it. After reading a lot of threads it mentions converting this carb to a non feedback carb. I have several questions.

1. What is the actual difference between a 2150 and 2150A carb?
2. What does Feedback mean?

The carb I have has most of the lines plugged. The only connections on the carb are the throttle linkage, wire going to the choke adjustment and the fuel line.

It was this way when I got it. Currently it runs cold. I have to pump the gas 3 or 4 times before it will start and then it needs to warm up for 5 minutes or so or it will die when I take off.

It also has not getup and go when I press the gas. I dont expect it to chirp the tires but it lags a lot.

The factory tach does not work either. Not sure it is related.

Full disclosure: Thinking the fuel filter needed to be changed I changed it and while tightening it, I cracked the bowl. I was able to seal the crack temporarily but I would like to replace the carb.

3. Could I get a 2150 and swap it out?
4. If not what will I need to do to replace it with a different type of carb?
5. What type of carb should I get?

Any info will be greatly appreciated.
rick

 

If this was a feedback carb, that means you have a computer somewhere to run it, and that also means you probably had computer controlled timing. If your distributor does not have a vacuum line going to it with a vacuum advance on the side of it, then yes you have a computer controlled distributor, and if that's not working either because all the other sensors are disconnected, then that's the reason it has no power.

Do you have any type of inspections? How close do they look? If it where mine, I would save up and find a used cast iron 4bbl intake, or buy a new aluminum one. I would then buy a small 600cfm holley or a small edelbrock 4bbl and install that, along with a new distributor. You can get a duraspark II unit and a ignition module for it, or get some other ignition system that you would like to run, that would have the old type mechanical advance and vacuum advance units on it to control the timing. You will be surprised how much this carb and distributor team will wake this engine up.

The feedback carb had a passageway with a solenoid mounted in it. The solenoid when activated would add more fuel to the engine. The computer would look at the oxygen sensor, and would cycle the solenoid more or less to control the fuel going to the engine. It just tweaked the fuel delivery, as you have found out it will still run with it disconnected, just not very well.

 

Hi Rick - I've just done what you are looking at, with my truck - also an 83 F250.

1. A 2150A is the feedback version of a 2150. An ordinary 2150 has no computer related electronics.

2. A feedback carb gives electronic 'feedback' to the truck's computer from several sensors, along with an O2 sensor in the exhaust; the computer then fine-tunes the mix accordingly, via an air-bleed solenoid on the back of the carb.
The feedback 2150A still has conventional jets - the air bleed unit just gives constant fine tuning adjustments.
Disabled like yours, it will run at the rich end of it's range - but this isn't extremely rich; mine was the same way for a while, but the plugs were still not black.

3. Yes it will bolt straight on, but as Dave (Franklin2) said, the distributor & module also need to be changed to Duraspark II.
When I bought my truck a previous owner had already done the ignition swap from Duraspark III, but had left the feedback carb on for inspections in California.

I found a non-feedback 2150 & recently re-kitted it, then tossed the original 2150A, along with the computer & emissions gear (3x large boxes of stuff!).

There's a huge number of differently calibrated 2150's, so you need to get one that's at least an approximate match to your engine.
On the drivers side of the float bowls are some numbers, cast inside a circle - e.g. 1.08, 1.21 etc......this is the carb venturii diameter, & needs to be matched to your engine size. There are also other differences according to year & vehicle etc.

With an auto trans, you will want a carb with the kickdown lever on the throttle shaft.

Your cold-start problems are probably just from the choke needing to be set up again, assuming the normal adjustments (float level etc) are all OK. The non-feedback 2150 has the same basic choke as you have now.

 

Thank you for all the information. Since I am not a mechanic, is it possible to get an idea of what I would need to get to make this truck run right?

Like what carb and distributor I will need to get?

There are so many choices.

Rick

 

What engine does it have? A 302 or a 351w I assume?

 

It has a 351W. Auto. 4x4.

There are no connections on the carb except the throttle linkage and a little wire going to the choke.

Rick

 

That's pretty much all a non-feedback 2150 needs, although there would also usually be hot air tubes between the carb & exhaust manifold; these might have rusted/broken off. The air tubes & the power supply work together to heat & open the choke as the engine warms up, but they seem to still operate OK on electric only (maybe not so well in an extra-cold region). If the tubes aren't used, there are two ports that need to be blocked off on the carb.

The throttle cable, fuel line, air cleaner, kick-down linkage etc, will all swap from your carb straight onto a 2150 (it needs to be for an auto trans vehicle), & the stud pattern is the same.
The venturii size (numbers on the drivers side of the float bowl) for a 351 would be 1.21". If you find a carb with it's ID tag still on, you can go to a carb site & use the tag to get a kit for it e.g. -

Chicago Carburetor

Motorcraft 2150 Carburetor Parts

Someone else will know, better than me, regarding the distributor/module/harnesses etc.

 

So I will not need to do anything with the distributor? From what I have read on this site, lots of people are converting to a Duraspark system from the Feedback Carb?

I would just like to swap out the carb without having to do the ignition and distributor change out.
I have found a couple of places where I can get a carb that will swap out.

Carburetor Lookup
The guy at National said it should work.
Rick

 

Do you have a vacuum can and a vacuum hose on the side of the distributor? If not, you have no way to control the timing of the engine. It has no weights down inside the dist to advance the timing when the rpm rises. And it has no way to control the timing according to the load on the engine. It's very important that it works correctly.

 

Dave is 150% correct. If it were me I'd replace the distributor, assuming you don't have the vacuum advance on it, long before replacing the carb. Changing to a non-feedback carb might get you a bit better driveability, but changing to a DS-II distributor from a computer-controlled one will make such a huge difference that you won't worry about the carb.

I'm not taking anything away from Ken, as he knows far more about those carbs than I do. But, w/o the right distributor the engine's timing is locked at something like 10 degrees BTDC instead of changing with the engine's needs up to something like 34 degrees BTDC. That is a tremendous change, and without it no carb is going to make the engine run even remotely correctly.

 

Yes, look at your distributor and figure out if you have a vacuum advance on it or not... could be a PO replaced the carb some time ago - did half a DS2 swap - and the computer is freaked out about that and therefore not advancing the ignition timing.

So, you need to determine what type of distributor you have in the thing.

Pictures would be marvelous.

 

I'm not sure where the confusion came in, but I'm not suggesting to only change your carb.

If the system you currently have is Duraspark III (having no vacuum advance unit on the base of the distributor), it will need to be changed to either Duraspark II, or a stand-alone aftermarket unit.

 

Duraspark (whether I, II, or III) is the ignition system, not anything directly to do with the carb.
The connection is that feedback 2150A's were installed on engines with Duraspark III distributors.....both being computer controlled, & operating together as a system.

But Duraspark II distributors, & non-feedback 2150 carbs, operate independently of each other (except for a vacuum source) in vehicles with no computer.

 

Ken - I knew you weren't suggesting to only change the carb. But it looked like Rick took it that way, so I was trying get his attention.

 

Thanks Gary......I guessed that was the case.