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Technical Carburetor problem - 351 Cleveland

Discussion in 'The Hokey Ass Message Board' started by HOTRODPRIMER, Feb 12, 2019.

  1. I have a 4 barrel carburetor on the 351 Cleveland that is in my '50 Ford Coupe and it runs great after it warms up but despite all the things I have tried the engine dies every time I stop at the traffic light or stop sign.

    I have rebuilt the carburetor.

    I can brake with the left foot and keep my right foot on the gas feathering it and it doesn't stall.

    I tried idling the speed but then it idles too fast.

    Any of you carburetor gurus have a suggestion? HRP
     
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  2. gene-koning
    Joined: Oct 28, 2016
    Posts: 4,040

    gene-koning
    Member

    The 1st thing I would suspect is a vacuum leak. Do you have power brakes? Are you installing a new carb base gasket every time you take the carb off? Didn't miss a vacuum hose on the rebuild did you? Are the vacuum hoses all good? Hoses are things we often reuse without thinking they may not be sealing on the carb fittings, or may have cracks at the tight bends. Gene
     
  3. One possibility, is that one or both floats are set too high. What kind of carb is it? With a Holley, and it has the sight screws on the bowls, it is just a matter of pulling the sight screws and checking to see if fuel is flowing out the hole. If it is a QuadraJet, Carter, Autolite, or Edelbrock, then you are going to have to pull the top to adjust the float downward very slightly to lower the fuel level in the bowl.
    Bob
     
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  4. 6sally6
    Joined: Feb 16, 2014
    Posts: 2,459

    6sally6
    Member

    What's your TOTAL timing?......34-36*? Most engines with a snotty idling cam want more initial timing16-18*?!
    Lighter springs will give you a quick advance(a good thing) but sometimes it will allow the engine to continue up to 40-46* and up (a bad thing) You need to limit the total to approx. 36* and set the initial to 20*. Idle will be crisper and higher. THEN turn down your curb idle to where you want it.
    These numbers are not cast-in-stone but you get the idea. Lotsa initial timing works miracles(until you have hot-start issues) Then we can "fix" that!
    6sally6
    PS............Gene Cromer can clue-you-in I bet.
     

  5. flamedabone
    Joined: Aug 3, 2001
    Posts: 5,440

    flamedabone
    ALLIANCE MEMBER

    Where is your timing and where is your vacuum canister attached? And, of course, what kind of carburetor?

    -Abone.
     
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  6. theHIGHLANDER
    Joined: Jun 3, 2005
    Posts: 10,244

    theHIGHLANDER
    ALLIANCE MEMBER

    Put me in the vacuum leak line too. I never liked the ether spray idea to detect leaks, too scary. I like a propane torch (unlit of course) because you're not spraying a volitile fluid on a hot engine. Works like a charm, and unless the engine is so damn hot it would melt the paint on the hood it's really quite safe.
     
  7. Does it start right away after it stalls? If it's a manual choke, try running it with a partial choke. This could tell you if it's fuel or ignition...
     
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  8. rockable
    Joined: Dec 21, 2009
    Posts: 4,429

    rockable
    ALLIANCE MEMBER

    Could also be trash in the idle circuit. After you've checked all these things, you should have it purring like a kitten.
     
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  9. Do you have a vacuum advance on the distributor? Does it hold vacuum or could it have a leaky diaphragm? Is it connected to ported or full manifold vacuum?
     
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  10. Check all your carb settings and adjustments
    What kind of carb?
    Vacuum reading ?
    Sounds like a vacuum leak to me.
    Have you futzed with the distributor or timing at all?

    Hook up a vacuum gauge, should point you in a direction.

    Remember a forest is nothing more then a bunch of trees, strat knocking them down and before you know it you have a clear field !
    Good luck keep. Us posted .


    1765B3E2-C0E6-4876-9712-191DF32A6542.jpeg
     
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  11. deathrowdave
    Joined: May 27, 2014
    Posts: 3,518

    deathrowdave
    ALLIANCE MEMBER
    from NKy

    What brand of carb are you using ? I hate to say this but , if me I would remove the dist cap and use a vacuum pump on the vacuum advance , watch the operation . It should hold the vacuum you pump it up to . If no hold the diaphragm is toast . Look for where the arm attaches to the breaker plate . If the arm is off that is your problem. Your vacuum advance should be attached above the plates on a Ford . Sometimes switching it will solve a lengthy battle , try that also. Give me a touch more info , I think we can narrow your issue down .
     
  12. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    Count me in with the vacuum leak vote.

    Second choice would be an electronic conversion (if it has one) in the distributor. Over the years, we have solved literally hundreds of "carburetor" problems by having the customer re-install points and condenser in their distributor. Seems that if they fail, it is always idle issues.

    Jon.
     
  13. Vacuum leak or crap in the idle circuit. I have had luck pulling crud through a partially clogged jet by running the engine at a high idle and placing my hand over the top of the carb, like I was smothering my step mother... snuff it out quick and sometime it works, that moment of ridiculously high vacuum is what does it. How is the gas filter?
     
  14. woodsnwater
    Joined: Apr 4, 2016
    Posts: 502

    woodsnwater
    Member
    from North Al.

    That's what we call a red neck tune up. It's worth a try before you move on to more invasive steps.
     
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  15. Zookeeper
    Joined: Aug 30, 2006
    Posts: 1,042

    Zookeeper
    Member

    Vacuum leak vote here as well. Look everywhere and like was reported before, don't spray flammable liquid on your engine. Best case is you have a messy engine with crap all over it, worst is the car burns to the ground and you don't need tp worry about that leak anymore.
     
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  16. Petejoe
    Joined: Nov 27, 2002
    Posts: 12,263

    Petejoe
    Member
    from Zoar, Ohio

    We call that burping it.
     
  17. stubbsrodandcustom
    Joined: Dec 28, 2010
    Posts: 2,273

    stubbsrodandcustom
    ALLIANCE MEMBER
    from Spring tx

    HRP... Honestly it almost sounds like the float levels need to be checked. Heat makes the fuel react different in the floats and sometimes they can be too lean when hot.

    I would run it around the block, get it to die in front of your house, pull a plug and it will tell you, wet or dry..... The only timing thing that would make this happen is if the advance got stuck. Not very likely....

    When you had it apart, did you clean the transition slots, air bleeds, back the idle screws out and blow them clean also? If a holley carb remove power valve clean passages and install new gasket etc also.

    Give the idle screws .5 turns out and see if that fixes or hurts your problem..... If worse, then go in .5 from baseline. It could be that simple now that i think of it.
     
  18. Heavy Old Steel
    Joined: Feb 1, 2019
    Posts: 96

    Heavy Old Steel
    Member

    Once it warms up it comes off the fast idle cam, then if the throttle plate clearance is tight or no clearance it will stall, this depends on type of carb you have.
     
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  19. rjones35
    Joined: May 12, 2008
    Posts: 865

    rjones35
    Member

    Years ago I had a Holley 4bbl that did that, driving down the highway fine, then pulled off and stopped and it died. Started right back up, but died at every stop after that unless I kept the rpm up. It was the mixture. The screws vibrated out. Got it adjusted again and it was fine.
     
  20. Thank you all for taking the time to respond, With ladyhrps business natures corner florist the last couple of days have been extremely busy and I have been playing delivery boy and haven't had a chance to look at the car or check on the thread.

    I hope to check everything this weekend. HRP

    I didn't noticed any leaks,I did install a new carburetor gasket, the vacuum hoses are new

    Could be float related, it's a Holley carburetor,.

    The timing is set somewhere between 10 and 18 as I recall.

    Timing is between 10 & 18, it's a Holley carburetor and I don't have a vacuum canister.

    Yeah, The engine fires right up and it's a electric choke

    Anything is possible.

    The vacuum advance appears to be working properly but I will recheck.

    I'll try some of these suggestions this weekend.

    More stuff to try this weekend.

    Every thing is new in the distributor including cap, I'm going to stick with points ignition.

    New fuel pump, new gas filter near new gas tank, new gas lines, new filter near carburetor and rebult Holley carburetor. HRP

    Everything was cleaned properly & all the gaskets were replaced.

    This is the symptom and I'm tired of doing the toe dance to keep the car running, I really shouldn't have to do that. HRP
     
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  21. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,215

    2OLD2FAST
    Member
    from illinois

    Holley's have places that you cannot see that need cleaning , even if you soak them sometimes you can't get them clean . The only way to access those areas is to pull the Welsh plugs out of the top or the metering block(s) . Holley also has passages in the base plate that connects the primary and secondary idle bleeds. If the base plate gasket is the wrong one you'll have an idle vacuum leak ........
     
  22. I found a cure for cleaning the impossible passages on small carbs and the Holley metering blocks. I bought a cheap Chinese ultrasound cleaner and use a heated solution of solvent (outside), or Simple Green, and run the carb parts I am cleaning, a couple of 10 minute cycles.
    You can actually see the crud being washed out of the plugged ports.
    It has saved me a ton of money, by allowing me to clean my auto parts, as well as the 2 cycle carbs on my trimmers and chainsaws. It is also handy for cleaning any other intricate parts.
    I have the smaller 1 quart tank, but because of the time and money saved, I regret not buying a unit with the larger tank.
    Bob
     
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  23. You see... This right here is why electrical diagnosis give me the heebie-jeebies. :eek: You'd figure that at an idle condition the ignition system is seeing probably the least amount of load or stress possible. o_O How could an electronic ignition system possibly work at all but end up not letting an engine idle with no real load on it? :mad: AAaaarrrrRRRGGHH!
     
  24. X-cpe
    Joined: Mar 9, 2018
    Posts: 1,958

    X-cpe

    Built a 327 that ran like that years ago. Put a genuine, hot lick, no-name, guaranteed better than an L79 cam in it. Idling out of gear it made just enough vacuum to pull in the vacuum advance. When it was put in gear the idle speed dropped and vacuum went below sufficient. That allowed the advance to retard which dropped the idle speed below critical. If we set the idle speed high enough to idle in gear, it raced like crazy out of gear.
     
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  25. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 12,600

    Johnny Gee
    Member
    from Downey, Ca

    How your vacuum is/was hooked up (full vacuum) would do that. But is HRP running his advance unit as you have?
     
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  26. deathrowdave
    Joined: May 27, 2014
    Posts: 3,518

    deathrowdave
    ALLIANCE MEMBER
    from NKy

    Carb cleaning the ultra sound is tops in cleaning . I also use an old crock pot with solvent heat it up a bit move the stuff around , soak do this five or six times and it’s spotless. I’m still leaning towards ignition timing issues . Fords are funny about timing issues , get it right and it’s bullet proof get it wrong and you be damned until you locate it . Cleaning stuff to share : We had a huge oven , at work to burn insulation from electric cable before scraping it . Man that thing would clean engine block , heads , trans cases , really any thing that was greasy . It was so clean in the climate where the humidity is 90% daily if you didnt oil your junk it was rust . Sorry had to share cool stuff .
     
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  27. 6sally6
    Joined: Feb 16, 2014
    Posts: 2,459

    6sally6
    Member

    See may "remedy" about running ALOT of initial advance above. Really cleans up the idle. Helped my SBF with a killer /snotty cam in it.
    6sally6
     
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  28. s55mercury66
    Joined: Jul 6, 2009
    Posts: 4,335

    s55mercury66
    Member
    from SW Wyoming

    Danny, are you running an Autolite distributor? If so, they change the dwell drastically when the vacuum advance moves the points plate. The one in my '66 will change 15 degrees, so initial point setting is very critical. Set them and then check with a dwell meter. I have thought very hard about running a Pertonix or other electronic setup for just this reason.
     
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  29. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 12,600

    Johnny Gee
    Member
    from Downey, Ca

    Dwell should not change when breaker plate moves. There is issues if it does.
     
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  30. s55mercury66
    Joined: Jul 6, 2009
    Posts: 4,335

    s55mercury66
    Member
    from SW Wyoming

    Take a look at an Autolite distributor, it does.
     
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