Hi, I'm posting on behalf of my son who has an 82 f100. It's pretty much stock as far as I can tell. He asked me to find recommendations about carburetors. He doesn't know if he should buy a new one, get a rebuilt one, or rebuild his own. Is there a specific carburetor that is better than others?

He has never done any kind of rebuild before. His experience stops at installing a battery, and spark plugs.

 

Well MJP we need some more information here.
First why does he think it needs a carb? What is it doing or not doing that he want to try and fix?
Could be it just need an adjustment to work as it should or even a simple rebuild or may not be anything to do with the carb?

Now the big question what motor & carb does this truck have?
I think either the carter v1 on the 300 six or the motorcraft v2 on some of the v8 motors are an easy carb to rebuild and think he could rebuild either.
Dave ----

 

Hmm... Ok... I will have to ask him that I know he's had some trouble out of it for a few months now. It was adjusted, then started running roughly again. Someone cleaned it for him, but did not rebuild it. It was fine for a while, and then started running roughly again I will talk to him this evening and find out exactly why he thinks it needs to be changed I will also find out about the motor All I know is that it's a v8 and a 2 barrel carburetor 🤷*♀️

 

also ask him if the truck had been sitting for a bit?
What fuel filter(s) he has on it and where they are to the tank & pump? I ask because some people put a plastic see thru type filter between tank & pump because of rust in the tank.
People also put a plastic see thru type filter between pump & carb.
I think the factory fuel filter was metal body filter screwed into the carb but could be wrong?

On his carb my thinking it is a Motorcraft 2100 or maybe a 2150, both should be easy to rebuild and the rebuild kit not much money.
From what little you said it could be rust getting into the carbs fuel bowl and "gumming it up" because you said it was cleaned and ran good for a bit.
Have him also check all vacuum lines & caps to make sure he does not have a vacuum leak as that can make them run bed.
Dave -----

 

Thank you so much. I do know that fuel filter is metal. He just replaced that not long ago. Actually he replaced it twice due to over tightening the first replacement. It did screw into the front of the carb.

 

First things would be basic adjustments. Choke flap opening fully when warmed up? Idle mixture screw set right?

You will have a few air (vacuum) lines coming off the carb to various other things. If one leaks it will run poorly. Fuel filter as mentioned above? Dirty air filter? If the truck has been sitting for a while bad gas, rust in the tank, maybe even water could cause issues. Another easy check is look down the carb with the engine off, press the throttle and see if the accelerator pump is squirting fuel into the primary barrel(s). Maybe check cap, rotor, plugs, worn ignition parts will cause poor running.

Not familiar with the 2 barrel, no idea how hard it is to rebuild.

 

Ok, so he uses this as a daily driver. It runs "fine" while he's moving, but when he sits at a red light or idles for a bit, the idle drops really low. At a stop, he puts it in neutral and holds his foot lightly on the gas to keep it running smoothly. How do we find out exactly which carburetor he has? It does say Motorcraft

 

Here's a good site that will help you ID that carb:

https://www.carburetor-parts.com/How...t_ep_42-1.html

I bought a rebuild kit for a Motorcraft 2150 from them. They have decent prices and high quality parts.

You can rent a vacuum gauge and other tuning gauges from an auto parts store. Put a vacuum gauge on one of the vacuum nipples that has vacuum at idle and let us know what the reading is. You should have 15+ inches of vacuum.

 

Awesome. Thank you so much!

 

I will start with the carb. You said it was a v2 and Motorcraft so guessing either a 2100 or 2150 and pretty easy to throw a kit in.
There should be a metal tag with numbers on it under 1 of the screws that hold the top cover on. With that number you should be able to get a kit for it.
If no tag you will have to "wing it" and get the kit for the year truck & motor size. Most kits fit a few different carbs of that model and you are really after the gaskets & float needle / seat assy.

Now this I will can it "stalling" does it happen when up to normal temp or when cold?
Should back up some what shape is the motor in?
By that how many miles on it? Have you done a compression test on it?
When was it tuned up last: plugs, plug wires, cap & rotor, air & fuel filter changed.
Timing checked to see if it is with in factory spec.
Has anyone checked for vacuum leaks? Use carb cleaner and with the motor up to temp and idling spray around the base of the carb, any where vacuum lines connect to the intake, also spray along the intake to heads. If there is a leak the motor should change RPM and that is where the leak is.

If a tune up has not been done I would start there and when plugs are out do a compression test.
If the compression test does not show anything bad then move on to other things.
If compression is bad then more testing will be needed to find why it is bad but most of the time it means digging into the motor: pull the heads for a valve job / rebuild the motor because of bad rings/pistons.

But lets not get to far ahead here, compression test and report back.
Dave ----

 

I am sure that we need to do all of those things. He has only owned it for a short time. Spark plugs, air filter, and fuel filter were changed The guy he got it from drove it daily to work, 20 miles each way. I will find out about the mileage, and we will definitely start looking into testing things as you've said. Thank you so much

 

You say he replaced the fuel filter twice due to over-tightening the first one. He didn't crack the carb when he over tightened, did he?

 

I don't think he did, but I can't be sure. I guess we'll have to take a close look at it.