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Technical Edelbrock flooding problem

Discussion in 'The Hokey Ass Message Board' started by JReece, Jul 9, 2016.

  1. JReece
    Joined: Oct 6, 2011
    Posts: 326

    JReece
    Member

    Hey guys, I rebuilt a 600 Edelbrock carb today. Now it floods from the primaries at idle. It's dribbling out so much fuel that the idle screws do nothing.

    I took the top back off of the carb and adjusted the floats to 5/16. It still does the same thing. I was using a Carter kit. Edelbrock says to use 7/16, but I'm not sure that's the problem.

    Anything else I might have done wrong?
     
  2. JReece
    Joined: Oct 6, 2011
    Posts: 326

    JReece
    Member

    I also switched out the step up needles with another carb I have. That didn't help either.
     
  3. what is your fuel pressure?
     
  4. JReece
    Joined: Oct 6, 2011
    Posts: 326

    JReece
    Member

    I put on a brand new stock mechanical fuel pump today. It's a pretty much stock 302.

    Not sure about fuel pressure though.

    The old fuel pump was starting to crap out, so I thought it might have been starving, until I fired it back up and did more investigation.
     

  5. PKap
    Joined: Jan 5, 2011
    Posts: 593

    PKap
    Member
    from Alberta

    I needed to use a regulator on three vehicles with stock pumps. My international truck was putting out 8.5 psi . Much better at 4 psi for the carb. I would do that before messing with the carb at all.
     
  6. Budget36
    Joined: Nov 29, 2014
    Posts: 13,173

    Budget36
    Member

    The Edlebrok spec for the float is 7/16th (least on the 1407 I just went through), 5/16th would be higher, right?

    Yeah, and FP is always a concern with them.
     
  7. JReece
    Joined: Oct 6, 2011
    Posts: 326

    JReece
    Member

    Yea, if I set it to 7/16, that would lower the level a little more.
     
  8. Budget36
    Joined: Nov 29, 2014
    Posts: 13,173

    Budget36
    Member

    I was hoping I had it right...was just a few weeks ago when I went through mine...but if 7/16th will lower it...you're looking at an 1/8th of an inch...huge.
     
  9. Where did you get 5/16"? Sometimes they run over at 7/16".
     
  10. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,856

    Mike51Merc
    Member

    The inlet chamber leading up to the needle valve must be perfectly clean on these carbs. The slightest piece of debris will allow that needle to seep fuel.
     
  11. Like said earlier, check fuel pressure and you will probably need a regulator to get it to 4 psi. I think the Edelbrock calls for around 5 . Mine is set to 4 to 4.5 and works great.
     
  12. Agreed! They do not like pressure, 5 being about max.
     
  13. JReece
    Joined: Oct 6, 2011
    Posts: 326

    JReece
    Member

    The Carter AFB Kit I had said to put the floats at 5/16. Sounds like I definitely need to put it at 7/16.

    Also, my dad put a regulator on it today. He even rabbit down to 2 psi, but it still didn't help.
     
  14. JReece
    Joined: Oct 6, 2011
    Posts: 326

    JReece
    Member

    Are you talking about the main fuel line coming in to those needles?
     
  15. Joliet Jake
    Joined: Dec 6, 2007
    Posts: 536

    Joliet Jake
    Member
    from Jax, FL

    I've owned and worked on many of these, sounds like improper float setting. This recently happened to a buddy of mine, I told him it sounded like a float issue, he sent me a pic of the floats. They were way out of adjustment.
    Download the Edelbrock carb manual.
     
  16. FityFive
    Joined: Aug 9, 2010
    Posts: 338

    FityFive
    Member

    How much vacuum does your engine have at idle? If you don't know, you can get a vacuum gauge from your nearest parts store to check.

    I ask this question because if the springs that dictate step up rod movement are too strong then you will get flooding at the primaries.

    Step up springs should be roughly half the engine vacuum at idle.

    I also concur that the floats need to be set at 7/16.
     
  17. I was going to mention this too. They don't like lots of fuel pressure.
     
    APACHE FS likes this.
  18. JReece
    Joined: Oct 6, 2011
    Posts: 326

    JReece
    Member

    Not sure, but the step up springs are pretty light. I'm guessing stock for the car, but you can watch them pull all the way in when the car is started.

    I definitely need to re-adjust the floats to 7/16.
     
  19. Joliet Jake
    Joined: Dec 6, 2007
    Posts: 536

    Joliet Jake
    Member
    from Jax, FL

    Look for the simple stuff, it's always the simple stuff.
     
    Montana1 likes this.
  20. JReece
    Joined: Oct 6, 2011
    Posts: 326

    JReece
    Member

    Well, I readjusted the floats, they are correct now. The needles are new and clean.

    The car is now running and not flooding.

    But, the right idle screw does nothing and it only runs on 4 cylinders when in gear. It's an automatic, so it's pulling down the rpm really low when in gear.

    At neutral idle, it seems to run fine.
     
  21. Morrisman
    Joined: Dec 9, 2003
    Posts: 1,602

    Morrisman
    Member
    from England

    I had this problem on my Edelbrock, fuel dripping in at idle, Stripped and clean a half dozen times, with no change, adjusted floats several times etc.

    Google research told me there is a tiny bleed hole in the bit that goes in the primary. It is tiny, but found it blocked with hard crud from dried out fuel.

    I think it was the very top idle air bleed that cured my problem.

    [​IMG]
     
  22. JReece
    Joined: Oct 6, 2011
    Posts: 326

    JReece
    Member

    Thanks for the image man, that helps a lot. I cleaned all of the small holes when I rebuilt it. They were pretty nasty.

    I believe I should probably shoot some carb cleaner in it and blast it with compressed air, like the image shows.
     
  23. fleetside66
    Joined: Nov 20, 2006
    Posts: 3,003

    fleetside66
    Member

  24. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,856

    Mike51Merc
    Member

    Yes. I bought a refurbished Edelbrock that flooded on it's first installation. At first I cleaned the needle and seats but then it flooded again. Turns out the inlet chambers leading into the needle valves were quite dirty. Some refurb, huh?

    Just as a sidenote, today's gas can wreak havoc on old rubber fuel lines. They tend to disintegrate from the inside, shedding rubber particles into the needle seats.
     
  25. DaveGoodson
    Joined: Jan 23, 2016
    Posts: 34

    DaveGoodson

    Buy a fuel pressure regulator, hook it up and lock it down at no more than 4.5 psi.

    Sent from my SM-G920T using The H.A.M.B. mobile app
     
  26. JReece
    Joined: Oct 6, 2011
    Posts: 326

    JReece
    Member

    Hey guys, I got it fixed. Just the float problem. I put a regulator on it and it didn't help. Took it back apart and then adjusted the floats.

    We also shot some carb cleaner in the idle screw hole and put some compressed air to it. Now it runs perfectly!
     

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