Carter AFB Carburetor

Carter AFB Carburetor

 

AFB Carburetor Identification

AFB Identification

Look for 4 numbers followed by a S. Example 3445S. You may find other numbers stamped on the carburetor, but they are usually the part numbers of the part they are stamped on. An example would be 0-1654S.

The AFB (Aluminum Four Barrel) carburetor was produced by Carter for original equipment cars from 1957-1971. The AFB was then available as a high performance 9000 series carburetor up until the late 1990’s. Weber is currently making the AFB now known as the Edelbrock.The accelerator pump controls response when pressing down on the gas pedal. Too little squirt will cause a flat spot or hesitation, too much squirt can cause black smoke and/or sluggish acceleration. You can change the action of the accelerator pump by repositioning the accelerator pump linkage.The metering rods are of a step design and are controlled by vacuum and metering rod spring action. At low speeds the metering rodis dropped down into the primary main jets, thus partially closing off the flow of fuel. At higher speeds and less vacuum the rods pull up from the main jets allowing more fuel to flow.AFBs use mechanical secondaries. Punch the gas pedal and the secondaries will open.The early AFBs were not rated with CFM statistics, but the later performance 9000’s were.Learn more about the metering rods, jets and metering springs. See all of our AFB parts
Carter AFB Jets, Metering Rods & SpringsAFB Jet & Metering Rod Sizes

Carter AFB Exploded Diagram

 

Carb
#
CFM Venturi Diameter Bore Diam
3721 575 1 1/4 1 9/16 1 9/16 1 11/16
4121 1 1/16 1 1/4 1 7/16 1 9/16
4122 1 1/16 1 1/4 1 7/16 1 9/16
4132 1 1/16 1 9/16 1 7/16 1 9/16
4133 1 1/16 1 9/16 1 7/16 1 9/16
4136 1 1/16 1 9/16 1 7/16 1 9/16
4137 1 1/16 1 9/16 1 7/16 1 9/16
4147 1 3/16 1 9/16 1 9/16 1 11/16
4148 1 3/16 1 9/16 1 9/16 1 11/16
4204 1 3/16 1 9/16 1 9/16 1 11/16
4205 1 3/16 1 9/16 1 9/16 1 11/16
9400 400 1 1/8 1 1/4 1 7/16 1 7/16
9500 500 1 3/16 1 1/4 1 7/16 1 11/16
9501 500 1 3/16 1 1/4 1 7/16 1 11/16
9510 500 1 3/16 1 1/4 1 7/16 1 11/16
9511 500 1 3/16 1 1/4 1 7/16 1 11/16
9625 625 1 3/16 1 9/16 1 7/16 1 11/16
9626 625 1 3/16 1 9/16 1 7/16 1 11/16
9627 625 1 3/16 1 9/16 1 7/16 1 11/16
9635 625 1 3/16 1 9/16 1 7/16 1 11/16
9636 625 1 3/16 1 9/16 1 7/16 1 11/16
9637 625 1 3/16 1 9/16 1 7/16 1 11/16
4758 500 1 3/16 1 1/4 1 7/16 1 11/16
4759 625 1 3/16 1 9/16 1 7/16 1 11/16
4760 750 1 7/16 1 9/16 1 11/16 1 11/16
4761 500 1 3/16 1 1/4 1 7/16 1 11/16
4762 750 1 7/16 1 9/16 1 11/16 1 11/16

Carter AFB Pump Link

Tip – The AFB pump link, links the pump lever to the accelerator pump. When you look at the link installed from the front of the carburetor, it should look like a ‘S’.

Free Carter AFB Manuals

Please do not distribute these manuals, but please feel free to give out the link to this page.

Carter AFB Carburetor Manual

Application Carburetor
Number
Ford
V8 Fairlane, 500, Custom, 300, Police Interseptor 1957
2441s, 2441sa
Mercury
V8 Montclair, Monterey, Station Wagon & Turnpike Crusier 312 1957
2441s, 2441sa
1966 Chrysler, Dart, Dodge, Plymouth 4121s, 4211s, 4132s, 4133s, 4136s, 4137s
1966 Lincoln 4147s, 4148s, 4204s, 4205s

 

AFB Accelerator Pump Problem & SolutionThis is a problem that one of our customers reported to us along with the email conversations.Sorry to bother you. I bought kit 4011 for my 1958 Cadillac Eldoradro, Carter 2862S AFB carb. Can’t get car to come off idle, wants to die. Warm, choke off. Idles O.K., 500-850RPM O.K. But when I push the accelerator to increase the RPM’s avove 850, it wants to die. If I coax it past this spot, at higher RPM’s it seems fine. A stream of fuel comes out the two accelerator pump jet nozzles when I depress the throttle, so I think the accelerator pump is O.K. I’ve adjusted the two mixture screws. There is a big air adjustment screw located between the two idle mixture screws, I tried to adjust that also. (But I don’t actually know the procedure for this air adjusment) Once it starts getting past the stumble, I notice drops of fuel coming out of the primary venturi’s, and dropping down onto the throttle buterflies. (I would think it would be atomized, not drops?) I’ve disassembled the carb a couple times, the float bowls are about 1/2 full. I’m stumped, I didn’t have this problem before I rebuilt the carb. I didn’t remove any shafts or butterflies. I would appreciate any ideas you have to offer. Second update: I should have checked this before I sent My first e-mail. My problem is a lean condition. If I pour a lttle gas down the carb while it is stumbling, itstops stumbling and smooths out. So the question is: What causes a just above idle lean condition? Third update: I fully closed the big air adjustment screw located between the two idle mixture screws, and this helped alot. I moved the accelerator pump rod down to the bottom hole, and this seemed to help some. I stll have an off-idle stumble, but it’s driveable, it doesn’t try to stall, just stumbles. The stumble is smooth slow acceleration, not punching it.
Solution:
I took it apart again, and found a piece of debris partially plugging the small brass tube
feeding fuel to the primary venturi, (the small tube inside the bigger tube with holes in it)
The clue was, just above idle fuel would drip out of one venturi, (the bad side) No more hesitation, and I was able to open the air adjustment screw to set the idle speed.

 

Watch Our AFB Rebuild Videos

I recently purchased a leather accelerator pump for my Carter afb. I
soaked the leather in 3 in 1 oil overnight and installed the new pump
but am still a little unhappy with the pump shot. I have never been
able to get a very strong pump shot, even after adjusting the stoke
and installing the arm with the three holes since my carb did not have
the holes, only a single hole. Are there any tips or tricks to get a
stronger pump shot, there is currently a steady stream but it does not
seem to have any force behind it. I have two afbs and they both have a
very similar pump shot, somewhat weak. Is this just typical of afbs? I
noticed the Edlebrocks pump shot is substantially stronger and this is
basically the same carb, perhaps they upgraded it at some point. I am
still dealing with my off idle stumble and believe it may be a lean
condition due to weak stream from the squirters.

One odd thing I did notice. I swapped the two accelerator pumps from
my two afbs. While one pump inserted smoothly and tightly into the
well, the other pump would not, as if the well was a smaller diameter,
it seemed to bind up in the well. .The pump from the other still
worked well in the other afb. Confusing since both pumps appear to be
the 11/16 leather cup.

Any insight would be appreciated.

I have never compared an Edelbrock to and AFB squirt and that wouldn’t be a very good way to judge anyhow. If you are concerned about the main discharge not discharging enough, make sure the small passages are clear. Ethanol will leave residue in the carburetor passage ways. You will have to poke through the holes with wire. Test the pump before putting the top back on. Take a look at the Carter YF technical page. There is a video there on how to test the accelerator pump. Same idea for the AFB.

Soaking a leather pump in oil is not the best way to ready an accelerator pump and I’m not sure 3 in 1 oil is what should be used either. There are a lot of chemicals that do not play well with ethanol, so be careful. I keep all chemicals away from any carburetor. Only add 1 to 2 drops of regular oil before installing. Soaking in oil overnight probably has the leather swelled up past where it should be. I don’t know if the gas will eventually bring it back to a natural size or not.

Accelerator pumps do not necessarily fit tight in the pump well. Actually most don’t and shouldn’t, or the action will be too stiff.

 

 

 

64 thoughts on “Carter AFB Carburetor

  1. Mike,
    I am in need of the base assemble for a Carter 9627 carb because one of the mounting ears on my AFB carb has cracked off. Is that any possibility of buying a used base for my carb from you? If not do you have any suggestions as to where I could purchase a used base.

  2. HELP ! I have just recently rebuilt my AFB #3461 for my 327 vette . The engine starts up and idles OK. However under acceleration whem my seconderies are beginning to open the engine abruptly shuts down (as if its run out of fuel) It will continue to idle though. I have checked my float level and float drop. they seem ok. What have I done wrong? Thanks for your help. Joe

  3. I recently rebuilt my Carter AFB 4119s carb for a 1966 Plymouth Barracuda with a 273 using a carb kit from your website. Unfortunately, I broke both of the idle mixture screws in the process. I have been trying to find replacements, but they are all too small in diameter. Do you know how I can locate the larger diameter screws, other than buying another AFB core of the same vintage at a swap meet?

  4. I rebuilt the 3720s afb now it will not idle. It must have a vacum leak as I can get it to idle by partially covering the primary opening with my hand. I have removed and plugged all hoses and ports on the carb. Also have sprayed WD-40 at the base and throttle shafts for vacum leaks. I believe it to be an internal problem in the carb. Help! Please.

    • The 1st thing you will need to do is rebuild the carburetor again. Spraying WD-40 around a carburetor is a sure way of ruining your gaskets. Ethanol + WD40 = acid.

      The other side of a vacuum leak is not having enough fuel in the carburetor. Recheck your float level and make sure the needle and seat are working properly. Did you put the clip on the float and the needle? This helps lift the float when more fuel is needed. Also did you use a quality US made kit like we sell? We won’t use any imports because the needle & seats are trouble.

  5. I have a 66 Barracuda with a 318 (purple cam) and 3108S carb. I went to adjust the air/fuel mixture screws and turns them all the way in and it continued to run. I figure this is why it is running rich as well as small hesitations at lower speeds. The car doesn’t hesitate when I step on it, but I think it could run better. Any suggestions?

  6. I need to get a rebuild kit for a Carter AFB carburetor that is currently on a 327 chevy engine from 1963…not sure of the year of the carb, but do not find numbers on the carburetor where your diagram indicates….it’s stamped on the opposite side front (if in the driver’s seat, would be right front corner; there is not metal tag). Number stamped there is DI 9625 SA . Also, on the right side of the carb housing is either a C- or O-1862. I now see from the discussion above that 9625 is one listed and the housing number is a parts number. However, the numbers used to indicate compatibility on the ordering page do not coincide with these numbers. Can you advise as to what kit might work for a re build?…will 4011 work?

    thanks,
    john

  7. I have a Carter AFB 3507S in my 1963 Studebaker Avanti R-2. I have had rebuilt several times.but I always end up with the same problem. It will not hold an idle and a small amount of gas drips into the right primary venturi at idle. What is up with that?

  8. 1967 GTX, 4127s have been into this card 50 times. Can not get why the accel’ pump won’t work until half throttle. It seems it’s in the body. I have three 4127s, the other two work. All adjustments are spot on, bench test seems good, put on car, no dice. Traded inlet check, plunger, top, needle, squirt-er, cleaned bore, blows clear, take out squirt-er, hold finger on hole, no leak back to bowl………….I have only one hair left to pull, HELP

    • The 1st thing that comes to mind is the distributor advance. A distributor not advancing correctly will act just like a bad accelerator pump.

      Assuming the distributor is OK, turn your attention to the accelerator pump circuit. You 1st want to be sure the adjustment to the pump arm is such that when you press on the throttle, the pump starts to move right away. Any slack will cause it to hesitate.
      The next thing is to see if any fluid is escaping when the pump is depressed. You will need to remove the top of the carburetor (should be off the car), and remove the pump jet housing (I would call this the pump discharge). Fill the pump housing with fluid. Plug the discharge with your finger and press down on the accelerator pump. You should get some pressure. If not, then the fluid is leaking back through the check ball into the float bowl.

      Assuming there is nothing leaking back, fill the pump housing with fluid, and press down on the pump. Fluid should shoot up through the discharge hole right away. If not, then there is a blockage somewhere.
      By the way, be sure the check weight is in the discharge hole.

      We use mineral spirits for this type of testing.

      Make sure your secondary air valves are working. When the secondary plates are opened, the air valves will not allow air through the plates until the engine can burn the extra air and fuel mixture. This prevent hesitation during acceleration.

      Another possibility is the metering rod springs. These springs move the metering rods depending on the engine vacuum and bad or incorrect springs could also cause hesitation. This is especially true when running any kind of performance cam resulting in lower vacuum. Eperiment with different springs to see if the hesitation is removed.

    • Is an R-2 supercharged? If so, those carbs must be assembled a bit differently, with lots of attention paid to sealing in critical areas.

      Otherwise, I would guess that the carb keeps getting “rebuilt” with needles & seats which leak such as Pacer part # 25-278A. There is no reason for a raw gasoline drip into either venturi unless the bowl is overfilled. Of course, he could also have a hot-soak condition (gasoline percolation from heat).

  9. Hello Mike

    Trying to find what kind of carb i have.
    Carter AFB, E1 9500SA,

    Can you help me ?

    Greeting from Sweden
    Love the Videos :)

  10. I have rebuilt a Carter AFB 9635SA 2 times, and it won’t idle smoothly at all, it misses and pops, I had another one on there and it ran fine, but I sold it because I have too many carb’s, I found the primary jets are counter sunk in there holes 1/16 to 1/8″ down, I had stock 70×47 metering rods and it ran awlful, changed to 75×47 rods and it improved but still rough, changed rods to a Plymouth 318 2991S rods 16-120 and it ran much better but still rich, can smell it. Jets are pri. .100 and sec. .095, mixture screws are new but backed out 4 turns. what’s with this Carb, is it trash, I’ve soaked it in chem dry and pure acetone also and it’s clean.

    • Hard to say here, but I doubt your problem is with the jets or metering rods. Something is installed incorrectly, floats too high. Simply too much fuel getting in. Test your floats and make sure they don’t leak.

      • I will check my floats, it seems to have the idle mixtures screws out 3 turns to idle, and it idles with popping out the exhaust and it’s rough.
        No fuel is leaking out the shafts or down the bores

  11. I have two carter carburetors with a tag# 3681s. By the chrysler part and casting numbers book these fit 1964 hemi. I would like to see a photo of a 3681s carburetor to compare to what I have, to make sure this is right.

  12. I have a Carter AFB 4bbl Carb. with the numbers of 4B4 9637S stamped on the right front flange.. I am looking for a complete rebuild kit for this carb..Can you help me with this …. Thank You Stanley Lee
    urabus83@hotmail.com

  13. I’m runing dual quads on a 5.7 boat 202 aluminum heads 64 cc chambers straight plugs.jegs 350 260 hp goodwrench to start with stock cam 1.6 rockers
    jets running are 86 pri 71 mains 6252 rods 1 and a half turns on the avs
    34 degrees full adv after 3000 mallory marine dist no vaccum mallory coil
    500 cfm avs carbs and have probably possibly tried every combination possible
    jets pri+main rods etc. last try to really split hairs is to try a 71/74 main combination with a 62/52 and a 65/52 rod split up rich rod in the lean main side.etc. vsa versa front carb
    running 1/2 turn on the avs function to start motor is providing great top end and a lot of mid range torque! good combination a lot of time spent to get right .
    also had to go to mikes carter afb for /to get the smaller jets in the mains 71/71/70s he had them in stock hope this helps out some one.!!!!!!!!! rollie t.

  14. Mike, have a 9625 I’m rebuilding, when I pulled the Accell Pump Nozzle there wasn’t a ball or counter weight as shown on your video. What I extracted is a small needle valve. Kit has the needle valve and a ball, but will not allow nozzle to seat properly if both used, due to length. Due some 9625’s use set only?

  15. I am trying to figure out what kit i need to order for my 9100s – do you know if it is 450 or 500 CFM carb or maybe 400?

    My dad died 9 years ago and the nice buick 231 rebuilt by a race shop isnt running worth a crap? I figure i will put it in cleaner for a day or two – then replace the parts since it worked before he died.

    Also it will be 4 wheeling and i thought they sold different springs or some kit for off road?

    The intake is a edelbrock performer with performer cam but it has allot of power, or did?

    Thanks for any help,

    Rick

    • If 9100s is really the carburetor number, then you have a Carter TQ, or Thermoquad carburetor not an AFB. The kit for that carburetor number can be found here: http://www.carburetor-parts.com/Carter_Thermoquad_Carburetor_Kit_p/4270.htm

      Off hand I don’t know the CFM. I will try to find out and post it on the TQ technical page.

      As far as 4 wheeling, I wouldn’t do anything to the carburetor until after you rebuild it and test it out. Only then should you consider tinkering with it, because that is where your troubles could begin. :)

      Enter your carburetor number in our search box and the correct kit will be displayed.

  16. I just rebuilt my Carter AFB. It had a real dead spot before. It idled perfect. Now, there is no Idle and it pops and misses. As soon as the choke lets up it dies. Can you offer a suggestion?

    • The 1st thing I would look for is vacuum leaks. Check the flange gasket for fit. Other than that, you will need to carefully check the assembly process to see what went wrong. It might just not be getting enough fuel. Check all of the passage ways to make sure they are not plugged.

  17. I have a Carter ABS from a 1969 AMX. I did not see the part number for my carb in your tech information. Number is 4662S. Any idea of CFM on this carb?

  18. I believe they were 575cfm’s,
    What size is the air horn opening?
    there were 2 a 4-1/2″ and a 5-1/4″ does it look like the older ones with a round opening or like an edelbrock?

    • And the carb is either a AFB or a AVS carburetor.
      The AVS has a spring loaded secondary valve. the AFB is inside the secondaries down under the venturi’s and is weight controlled.

  19. Mike, I rebuilt my Cater AFB 9000 Series with your kit and videos. Worked out good. Old 1986 F350 runs good, but now that cold weather is here, it is not working correctly. During the summer I could start it up and the choke would be one but a quick pat of the gas and it would go off. Now it want go off at all. After starting. It will go up to 1500 RPS. a quick pat of the gas will bring it to 1,000, but as I am driving it, it will increase again. I can drive for miles, 20 to 30 miles and no matter what I do it will not ideal down. It stays at 1500 RPS. If I stop after it is warm and restart, it will ideal down to 700 to 800 RPMs. I tried turning the choke to decress by two marks from the normal and it did not do anything. I don’t know what I can do from here?

    • I can only make a guess because it could be a lot of things, but did you take the throttle valves apart? If you did make sure they haven’t come loose. They could be moving around and don’t wait too long because if the screws are coming loose they could fall into the engine. Aside from that it could be a bad thermostat, or some part of the choke linkage (or lever) is sticking. Check all of the screws that hold the linkage together. I don’t have a 9000 around right now to look at, so I can’t point out anything specific.

      Hope this helps.

  20. Hi mike nice vidios but I have 3 AFBs #s 3860sa also 3644 I want to rebiuld these and put them on a 6-71 blower 413 engine I need good kits can you tell me what CFMs are they are how much are the kits are will they run good on the blower do you have a phone # to call to talk

  21. hi mike it’s ray are the carb’ I have ok for a 671 blower or do I need 9000’s and do you have 2 good 9000’s for sale and how much would they cost

  22. I was rebuilding my 9400s and founf the choke housing piston is very stuck and wont move – it wants to tear the arm/connecting rod off the piston down in the hole?
    Do you have any suggestions – i wanted to make this manual choke anyway and the coil and that plate aren’t there?
    I thought about running an arm off the side of the carb that would clamp the outside of the choke cable and just connecting it to the choke tab where the linkage would go – if my choke housing worked?
    Considering i want it to be manual choke – do i need to fix the piston and how could i best accomplish this? I did see one carb that had an arm off the top ( behind airhorn) that was holding the choke cable jacket and was attached to the top tab?

    didnt know how many choke parts you have?

    thanks

    rick

  23. my Brother passed away and we found a Carter AFB Competition Series
    carb #9605s 0343
    Itrying to find information on this. I would like to sell it
    Tami

  24. i recently acquired a carter 9410 carb – i was told it was new old stock
    i can read the jets @ 392 & 371, but i cannot read the rods at all I think I make out 16-421? but this does not make sense from what ive found.

    Can anyone tell me what the original rods should be?

    thanks!

  25. I am trying to find an accelerator pump for a Carter AFB 4758S. I think i prefer the rubber over the leather. But i’ll take what i can get at this point. Do you know where I can find one? I dont know the diameter either since the leather on my current on is completely gone. Do i measure the diameter of the metal plunger without the leather? Or the diameter of the shaft it sits in? Thank you for your reply.

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