48 thoughts on “Carburetor Technical Information

  1. I have a 66 mustang 200 – someone replaced the non scv Autolite 1100 with one that has the SCV. I am having hesitation issues from a dead stop. If I do not feather the gas it will stall. Could the SCV carb be the problem? My distributor is correct for a NON-SCV carb

    • It doesn’t matter but the spark control valve might cause this problem if it is bad. Try replacing the valve, or at least put a timing light on and see if revving the engine makes any difference. Otherwise, it is probably in the accelerator pump circuit.

  2. Can the Carter Type YF carb designed for 1975-1982 Ford 250 six cylinder engines be used to replace my Autolite 1101 carb on my 1969 250 six cylinder engine? The original Autolite and a rebuilt Autolie carbs that I own have become unreliable. Amazon.com sells new Carter Type carbs which I hope will be more dependable if they are compatable to my 69 mustang.

  3. Help..please… I have 2 different 1904s tore down.. I managed to mix up the needles and seats. They all look alike and appear the same size. Does it
    matter? are they interchangeable? Can’t get either carb dialed in on my 144ci falcon anyway.
    Thanks Gene

  4. Hey sorry to bother you but I rebuilt my Motorcraft 2150 carburetor with electric choke. The truck is a pain to start but once running it runs fine as long as the idle is extremely high. Once warmed up I drop the idle and the carburetor will pop and stalls. So one time I tried to Rev the engine and nothing it was no responding to me reving the engine. Every piece of electronic is replaced

    • Hi,
      You either have a vacuum leak, or not getting enough fuel.
      Spray carb cleaner around the mounting gasket and any other vacuum source. If the idle smooths out, you found the problem.

      Lack of fuel:
      Carburetor gummed up.
      fuel pump not puttting out 5 lbs.
      clogged passageways.

  5. I have a Carter AFB carb in a Ford 460ci (1973) . The carb # 9637 SA 1218. The engine stumbles under acceleration at low speed or start of acceleration. Checked the accelerator pump and it is working. Any suggestions why this is happening?

  6. Last post, July 6: Was having a problem w/ accel pump install. Leather would fold back on itself during installation. After cleaning & sitting for a few days the pump installed w/o a problem. Procedure: I put a thin layer of 30W oil on pump bore & pump leather by first applying to finger then wiping on the parts. I’ve always used a spray lube but in this case it didn’t work. Thanks for the rapid feedback.

  7. Washed pump w/ carb cleaner, dried, and put back in sleeve for now. Will try later. When I oil pump I use a light spray lube, put some on a finger and wipe on the leather. Might dry out a bit and stiffen up some after a couple of days. I’ll inform of progress

  8. Recently purchased 2 kits for 64 mopar AFB (1 chrysler & 1 Plymouth) and had trouble w/ accel pump in one kit. Leather on pump folded back on itself making the pump inoperable. Pump bore polished, pump lubed. Several attempts failed. Leather seems to be too soft. Pump from other kit worked fine on bench and on road test. Cleaned discrepant pump w/ solvent and put back in cardboard tube for storage. Any suggestion as how to make this pump function properly?

    • Not sure what is going on unless you put too much oil on the pump. You only need a couple of drops. The gas in the well will cause it to swell up. When inserting into the well, twist the pump so that the cup doesn’t curl up.

      You might try washing it off with gas and let it dry a bit.

  9. I am rebuilding a rochester monojet on a 71 chevy truck. I can obviously see someone has drilled the main jet bigger. The jet has no markings and the metering rod indicates 078. The carb floods, and I cannot seem to adjust it. Will I need to replace the main jet? And what size?

  10. Mike, I just rebuilt a holley model 1920 and now it looks like I need a new fuel pump. What range of fuel psi do I need for my one barrel holley carb?

  11. Are the #12-28 screws used on the BB series (specifically the BBR-1 D6H2, and the ETW1) available most are seam to be 1/2 inch long; except onth ETW1 which aslo has some 3/4 inch long screws. I’ve been looking but can’t seam to locate any.


    1586053 OR 8

  13. ‘Revving up but won’t run on starting -up problem’…….Need some advice please on my ’49 pick-up truck carb BBR1 -633-S………had my engine running OK about 6-9months ago(I’d sripped the carb down,cleaned it up,fitteed new gaskets etc & on refitting engine ran fine) & been busy with the bodywork since…tried firing her up yesterday but will not continue run…….turns over fine (excellent battery power,good spark at plugs etc.) with the usual slight coughs then after a bit of petrol accumulation in the throat just suddenly revs up and promptly dies again this routine continues on starting attempts.. accelerater pressure ‘on’ /part throttle/ or ‘off’ makes no difference at all ……………I’ve just realised I’ve forgotten to remove the tape completely covering the tank filler neck (because of restor.working in the cab etc) and need to refit the filler cap …would this oversight on my part reduce the pressure to the carb & cause at least one problem / add to to the one I’ve got about the ‘revving-up’ but won’t run……..its abit dodgy working on the carb ‘in situ’ so its usually ‘a bench job’ to be on the safe side………..any pointers for me to check-out…..it would be appreciated…cheers…Colin

    • So: I would suspect a float level which is set ‘WAY too low.

      Perhaps the adjustment needle(s) may be turned too far / all the way in.

      Some orifices (possibly those non-replaceable ones drilled right into the casting) may be clogged.

      It could very well be a Viton-tipped needle which has not been properly cleaned of mold release residue sticking in its seat.

      On the other hand, he could have a rusted-shut steel fuel nipple coming out of the gas tank or the fuel filter (this happened to my own tractor) or an altogether-clogged fuel filter.

      He could also have a collapsed fuel hose (ALWAYS replace with fuel-injection grade!).

      Or he could have a bad fuel pump if the carb isn’t fed by gravity.

      He could also have a plugged gas tank vent.

      That’s about it — best of luck!

  14. Carb on a stock 1996 Kawasaki 800A leaking fuel out the over flow and throat like there is no needle valve at all. I have replaced the needle, gaskets and plastic float. Even taken carb off the bike and hung the tank up above while checking things out. Thought I had it twice but after 5 or 6 miles it started back leaking. Thinking the new float is doing it’s job.

    • I don’t know much about motorcycle carbs and it looks like you have done your homework, but one thing does come to mind. It is probably a foreign kit and they just haven’t had what you would expect to be a good fitting parts.

      Asside from that be sure to wipe off the viton tip of the needle until there is no black coming off. Use Berrymans carb cleaner for this. B12, I think it’s called.

  15. hi there mike
    i have been looking the web for info on solex carbs came across your site and enjoyed the info
    i have a 1974 volvo-pent aq130c with duel carbs looks like the 44pai without the extra fuel tube.both carbs have only one tube witch is from the accelerator pump last time i had the boat out both carbs started flooding at around 1800rpms i may need to rebuild the carbs the only markings to be found on both carbs were the solex casting numbers both were the same they are solex 70735 would you by any chance have kits and info on them if so may i get price and avlabity and i do use the boat alot i fish for trout,striper,sturgon,samlon witch covers most of the year so gas is not a problem again thanks for your help ,Rick

  16. I need the entire choke assembly for an old rochester 2gc. It’s an old carb and would have had a brass tag as there are no numbers stamped on the float bowl. The choke asm. is the spring and cap with a nipple on it I’m told with the baffle plate. I would appreciate any help you could give me as this is the center carb for a 3×2 setup. I believe this carb is around ’57 vintage.

  17. I just rebult my carb with one of your kit for 2bb E choke rochester, the problem i think i have is that this carb may not be a marine carb. hard starting, seem to be flooding once it gets started and at running temp. i did not change the float soo i’ll order new today. thanks for any info that you may be able to give me. Chris

    • If the float is nitrophyl, then by all means replace it. Obviously the carburetor is flooding, so think about what happens when fuel comes into the carburetor. Make sure the fuel isn’t bypassing the needle & seat. Did you install the gasket on the seat? Test it to make sure nothing is getting past the gasket. Test the fuel pump pressure. I don’t know what it would be for your application, but your engine manual should state the pressure. New fuel pumps are especially suspect. Recheck the float level. Check to make sure the float isn’t rubbing the sides of the float bowl. Did you use any teflon tape on the inlet threads. This is a sure way to get foreign matter into the needle & seat.

      It isn’t unusual for crud to enter the carburetor and dirty up the needle & seat after a rebuild and 1st starting.

  18. Hello Mike I have a 1988 merc. 4.3 with rochester 2 bbl. carb.#(3304-9565) The problem I have is sometimes when I start the boat it runs real rough i can see excessive fuel dumping into the carb when this happens,even after i shut it off fuel will spill into the carb for several seconds, when the problem is happening. I can shut it off come back later start it and it may run fine, or it may start acting up even after a long run on the water, when i back off the throttle it may or may not act up. The boat has fresh fuel, new fuel/water filter and plugs every season, Also all fuel i add to the boat gets treated with star bright enzyme, Supposedly my mechanic just rebuilt the carb. last fall. Thanks Kevin

    • It seems obvious to me that the carburetor is flooding. There are several things that might cause this. Bad float. You should have replaced the float when rebuilding. Could be a dirty needle & seat. The bottom line is that too much fuel is getting into the float bowl. Sometimes a fuel pump with too much pressure will cause problems, but that is usually when the fuel pump has been replaced.

  19. I just left you a voicemail.
    I have a TSX-936 Marvel Schebler carburetor.
    This is on a Case 470 tractor.

    I bought the carb rebuilt from All State Ag parts 2 years ago.
    They did not replace the throttle shaft and it is loose leaking air around the shaft so that it will not idle properly.
    I have to screw the idle screw all the way in to get the thing to idle, and then it’s still rough.

    So I need a new throttle shaft and a seal that goes around this.

    Also the venturi that site in the center of the carb has some damage so I might get this also if you have one and it’s not terribly expensive.

    I do not especially need the entire repair kit, but I would buy it if the throttle shaft was included.

    I have been looking for a parts diagram showing these part numbers but have not located one online so far.

    If possible also advise price & delivery on a new float for this TSX-936.

    Thanks for your help in advance.

    Benny Owen
    JAA Controls
    Dalton GA. USA
    Ph. 706-278-0849
    Fax 706-226-1558

  20. Overhualing Rodchester off a 1950 Chev 1/2 ton pickup. Lost the accel.pump filter screen (the one in the bottom of the bowl, helt in place by a snap ring). Is there a replace i can order, or can I just get some screen and cut one out ? If I can made my own, what size of screen ?

  21. I have a Holley series 4000 4 bbl carburetor. Do you rebuild these? If so what might it cost? I would like to have the electric choke added to this carb. I don’t have the old housing, but the linkage is there.

  22. Im looking to replace a cork float in an old johnson outboard carb. Its about an inch in diameter and an inch long. It doesnt seem to be available at the vintage outboard shops. is their a material I can use other than cork which will disolve with todays fuels
    this solid plastic material i have heard about??? Im working on Johnson td20. Thanks

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