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Technical WCFB leaking through primary Venturi

Discussion in 'Traditional Hot Rods' started by Omarsvette, Jan 19, 2020.

  1. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    ok so here’s my ride,
    31 ford with a 1954 hemi with original wcfb
    Been running good for 1100 miles when this problem began. I started it after switching a fuel filter and notice the motor fluctuate then level of to a hi idle, choke on. When I looked inside there was a steady stream of fuel coming out of both primary venturis. If I open the choke the stream settles to drop, but the car dies off within seconds. Never had this problem before.

    I have rebuilt the carb and drove it till this happen. Not one hiccup since initial rebuild. Since this issue I have :
    1) Re level the floats from way open to way close to setting them at factory setting
    2) new kit, needle and seat look good, cleaned the over again
    3) cleaned and checked, adjusted primary metering rods
    3) bowl vent cap readjusted per factory setting
    4) check and cleaned low speed jets
    5) moved electric fuel pump to rear next to gas tank, psi setting unknown
    On pump.
    6) psi on regulator set from 1.5 to 5, currently at 3psi
    7)when on, screwed in both a/f mixture screw close, nothing changes.
    8) placed floats in hot water, no leaks
    9) adjusted float drop, kept even with rear floats
    I haven’t checked for vacuum leaks because in my pass experience, that make for a rough idle? Mine is smooth, with the choke on, I can’t keep it on without the choke because fuel keeps dripping in. But the engine isn’t erratic. It seems like the motor is creating so much vacuum that is pulling fuel from the venturies. Air does pass faster through the venturies. That’s a lot of fuel going upstream. If it was sucking air from a bad gasket, it would be rough idle/high idle, like if the pvc hose came off?no stream of fuel coming out the venturies.
    Any ideas pleas!?!?!?!?!
     
  2. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    Here’s my floats 88068F80-5388-444E-9E8E-2FE4666874A7.jpeg
     
  3. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    457AF329-6E6B-4B06-A72B-B95BBABB9EF9.jpeg heres the carb, you can see how black the primary’s are from fuel
     
  4. Bert Kollar
    Joined: Jan 10, 2007
    Posts: 1,232

    Bert Kollar
    Member

    Just a suggestion, put a straight edge on the air horn, top casting to see if it is warped
     
    Elcohaulic likes this.

  5. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    2FC338D2-8068-4D00-8604-948D1CD86EE5.jpeg 3E0012ED-9355-4694-8785-38C86E0F93AC.jpeg EF210361-1860-4EC5-8F46-B7E389D8A40C.jpeg 148C48DD-B6F4-4FC2-8A6E-AC2DF562DC2A.jpeg
    I reinstalled everything , check air horn, it leans more to the rear but I think that’s engine placement?
     
  6. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    I just did the following after checking level, still leak
    1) covered with my hand the rear of the carb
    2) plug the rear two ventris with my fingers
    3) covered with my hand the front of the carb
    4) open the choke and plug with my fingers both ventris
     
  7. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    if I close down the choke more, more fuel gets squirted out even from the primary discharge.
     
  8. saltracer219
    Joined: Sep 23, 2006
    Posts: 1,071

    saltracer219
    Member

    If the float level is correct and the float does not have any fuel inside of it I would suggest changing out the needle-seat assembly. Check your fuel pressure, absolutely no more than 5 lbs.
     
    Blues4U likes this.
  9. Aaron65
    Joined: Dec 29, 2005
    Posts: 375

    Aaron65
    Member
    from Michigan

    I think Bert was suggesting that you check the flatness of the bottom of the carb lid, where it seals to the carb body.

    As mentioned above, I'd check the needles and seats, but in your picture above, the primary floats look way high; the secondary floats look about right. I'm not sure, however, what the factory setting is. You may want to pay extra attention to how clean your primary idle air bleeds and passages are. If they're at all clogged or scaled up, weird things like nozzle drip can happen.
     
    jimmy six likes this.
  10. TCTND
    Joined: Dec 27, 2019
    Posts: 543

    TCTND
    Member

    Be sure neither float leaks. A tiny crack can let gas in and drive you crazy. My fathers new '62 Corvair spyder came from the factory with a leaky float which the dealer mechanics found difficult to diagnose.
    regards
    Phil
     
  11. Bob Lowry
    Joined: Jan 19, 2020
    Posts: 1,488

    Bob Lowry

    I've worked with these carbs over the years a lot. I agree that the front floats are too high. I have always
    had them level with the top horn. It was always more important to have float drop set low enough to
    fill the bowl, rather than how high the float sat. Bob
     
    Omarsvette likes this.
  12. Mr48chev
    Joined: Dec 28, 2007
    Posts: 33,861

    Mr48chev
    ALLIANCE MEMBER

    This isn't the best instructional video you will ever see but he does hit a few points to check on the float adjustment. He did mention that on these carbs primary and secondary float level may not be the same too.
    One thing that was mentioned is making sure that the floats are true in the bowls as if one is angled off a bit it may hang up on the side.
    Maybe I'll get the right video this time
     
    Blues4U and Omarsvette like this.
  13. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    According to manual, primary float level is 1/8; secondary is 1/4. I’ve had both even lower with the same problem. I’ve put both float in cold and hot water, they float. Fuel pressure is 3 currently. I’ve had it at 1 and 5. N/s are new......
     
  14. oj
    Joined: Jul 27, 2008
    Posts: 6,454

    oj
    Member

    Floats are way wrong, make them level to the top when upside down. the secondaries are kinda ok but the primaries are way too high.
     
    footbrake likes this.
  15. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    The secondary are set higher, primary are lower, but looking at the pic, looks more than 1/8 or 1/4 haha.
     
  16. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    In the pic the primary floats are to the right next to the metering rods, right?
     
  17. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    Ok I think I get what y’all are saying about the float being to high, I’ll take it apart and make em level. Also the video mentioned the float should be in line so it doesn’t rub against the wall. I never check that.
     
  18. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    But it sounds like everyone agrees that’s either my floats or n/s is the problem? Right
     
    footbrake likes this.
  19. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    Ok so here my floats, with gasket off. Primary are to be set at 1/8 and secondary at 1/4. Should I level em off, just to try something different, cuz like this, my venturis are taking a leak in my carb! C9B97A13-6447-4381-BE22-029046159D17.jpeg EB81DDC3-3705-40C9-8637-0CB92CEB3570.jpeg 763B064E-CA35-4B5E-A470-99A823C869A6.jpeg
     
  20. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

  21. Fuel to burn
    Joined: Jul 17, 2009
    Posts: 285

    Fuel to burn
    Member

    Is low idle the only time you have performance issue?

    I'm not familiar with this particular carburetor but number 7 from your list caught my attention-

    "7)when on, screwed in both a/f mixture screw close, nothing changes."

    That makes me think your idle circuits are clogged.

    Sent from my SAMSUNG-SM-N920A using The H.A.M.B. mobile app
     
    jaracer and Omarsvette like this.
  22. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

  23. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    Ok , we agree I have a idle circuit problem. But would clogged circuits create this problem? If I disengage the choke, the car won’t idle because fuel is still dripping out the Venturi causing the motor to shut off
     
  24. Fuel to burn
    Joined: Jul 17, 2009
    Posts: 285

    Fuel to burn
    Member

    I would try cutting power to the fuel pump to see if performance improves when the fuel level drops.

    If it's a float level, needle and seat, or fuel pressure issue the idle should improve if the fuel level reaches the "sweet spot" before it eventually runs dry.

    Sent from my SAMSUNG-SM-N920A using The H.A.M.B. mobile app
     
  25. Aaron65
    Joined: Dec 29, 2005
    Posts: 375

    Aaron65
    Member
    from Michigan

  26. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    If you look closely, you can see the fuel spraying, below the choke plate, now this is with the a/f mixture screws COMPLETELY OUT, OUT OF THE CABR. I also switch the needle and seat from rear to front. I didn’t change the float level yet. image.jpg
     
  27. Fuel to burn
    Joined: Jul 17, 2009
    Posts: 285

    Fuel to burn
    Member

    If the choke plate is fully open does the fuel still spray from the venturi or does it just drip?

    Sent from my SAMSUNG-SM-N920A using The H.A.M.B. mobile app
     
  28. Using a drill bit or drill rod to measure the float level is more accurate than one eyeballing one of those scales...
     
  29. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,801

    jimmy six
    ALLIANCE MEMBER

    I have 2 WCFB’s on my Y -block and intentionally left the floats lower than specs especially on the front one since both aren’t used at normal driving. I have 1/4” phenolic plates under each one. No problems for 5 years.
     
    Omarsvette likes this.
  30. Omarsvette
    Joined: Dec 7, 2013
    Posts: 612

    Omarsvette
    Member
    from Arizona

    If I open the choke with finger, it’s spraying. If I knock it of the cam and the plate opens on its own then it drips and engine dies.
     

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