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Technical Edelbrock Carb Cold Start Problem

Discussion in 'The Hokey Ass Message Board' started by Conor Barclay, Oct 8, 2019.

  1. Conor Barclay
    Joined: Aug 13, 2019
    Posts: 6

    Conor Barclay

    New edelbrock carb on 289. I adjusted the idle mixture and speed when the engine was warm and with the air cleaner on and the car was running perfectly while warm yesterday. Go to start it up this morning and it rpms at about 2000 for a couple second then dies. Starting fluid, pumping pedal with get it too fire up but I can't keep it running. Choke is closed off fully. Fuel pump fills up filter as proper. All other carb settings are as set out of the box.
     
  2. irishsteve
    Joined: Jan 10, 2017
    Posts: 409

    irishsteve

    Any chance you have older rubber fuel line that has cracks? If so it will loose the pumps vacuum ,and you wont get gas.
     
  3. Mike VV
    Joined: Sep 28, 2010
    Posts: 1,579

    Mike VV
    Member
    from SoCal

    Open the mixture screws to 1-1/2 turns out and start the mixture adjustment again.
    To start the engine open the mixture screws 1/2 turn, see if that helps.

    Also, the choke butterfly should only be "just" closed. That is, lightly, but fully closed.
    If you try to open the butterfly with your finger, it should open "very" easily, but then reclose very lightly. You may have it adjusted too tightly.

    Mike
     
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  4. Yep... If it's fully closed right after the engine starts cold, then there's your problem. Check your documentation that came with carb for proper choke, high idle, and choke vacuum break adjustments. Also make sure the choke unloader is working properly.

    All this is assuming that you in fact have or want to have a working automatic choke. Are all the pieces there to properly rig up an automatic choke?
     
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  5. ahoover
    Joined: Jun 12, 2008
    Posts: 75

    ahoover
    Member

    Edelbrock AVS carbs don't use a choke unloader, "unloading" relies solely on the thermostatic choke spring. I would start by setting the choke coil in the center of lean and rich while the engine is cold, this will relieve pressure on the choke valve. Choke might be set too rich. Then in the carb manual look up and follow the choke adjustment procedure so you can get the proper gap between the air horn and choke valve. I would also check the float adjustment which can get screwed up in shipping. Now when you turn on the ignition and partly open the throttle see if the choke valve closes and leaves a small gap to the air horn. These carbs don't always run perfect out of the box, you will likely need to calibrate the primary metering as well. Is the carb sized properly for your engine? The manual has charts to show the effects of changing the jets and metering rods.
     
  6. tb33anda3rd
    Joined: Oct 8, 2010
    Posts: 15,110

    tb33anda3rd
    ALLIANCE MEMBER
    1. Connecticut HAMB'ers

    what intake are you using? does it have a heat riser set up on it?
     
    Last edited: Oct 8, 2019
  7. Conor Barclay
    Joined: Aug 13, 2019
    Posts: 6

    Conor Barclay

    It has an electric choke which I'm assuming is working properly. I spent a while adjusting it today, dialing in afr and idle speed and fast idle speed. I'm pretty confident I got it where it needs to be, but we'll see how it starts tomorrow when cold. I'm planning on going in further to the jets and metering but that shouldn't prevent it from starting up and running at the bare minimum. Its a 600 cfm on a 289 with a performer aluminum intake manifold.
     
  8. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,193

    dirty old man
    ALLIANCE MEMBER

    Checking the float adjustments is a good idea, as is going over the choke and idle mixture and speed settings. BUT LEAVE THE JETS AND METERING RODS ALONE TILL THE STARTING AND IDLE PROBLEMS ARE CURED.
     
  9. Conor Barclay
    Joined: Aug 13, 2019
    Posts: 6

    Conor Barclay

    I was thinking that taking the top off and making sure the floats are right would be my next course of action. I was assuming being that it is a brand new out of the box carb that the floats would be at least close enough so that the car would start without them being adjusted. And I'm pretty sure my choke is good. It's an electric choke, and its closed when cold and then slowly opens. That being said I think I'm gonna go to a manual choke. But it's not very cold where I live, about 40 degrees in the morning. I would assume I should be able to start the car in the morning even without a choke.
     
  10. miker98038
    Joined: Jan 24, 2011
    Posts: 406

    miker98038
    ALLIANCE MEMBER

    Don’t assume anything. 50 years ago I bought a brand new Holley carb that was shipped with jets 10 sizes small. The Edelbrock’s have very good manuals, if you don’t have it, get it on line. Read it till you understand it. I’ve done several 1406’s over the years, and I’ve got to have it in front of me every time I set one up.

    The electric choke should set up and work fine if all else is set correctly. But that manual is your friend, both now and when (if you need to) you get to the rods, jets, and springs.

    Adding your location would help, altitude plays into carb settings.
     
  11. Conor Barclay
    Joined: Aug 13, 2019
    Posts: 6

    Conor Barclay

    I'll head out and get the stuff for adjusting metering and jets etc. I'm hoping that it'll start at least tomorrow morning when cold. I'm in Victoria BC Canada, just up the street from the ocean so very low altitude.
     
  12. Happydaze
    Joined: Aug 21, 2009
    Posts: 796

    Happydaze
    ALLIANCE MEMBER

    I wouldn't assume that for a moment! It's possible but will need pedal pumping and it will be erratic and probably die a few times too. Operational choke avoids this completely. Been through this a few weeks ago with a new build I wanted to fire up but didn't have the manual choke set up (Edelbrock).

    Chris
     
    Last edited: Oct 9, 2019
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  13. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,193

    dirty old man
    ALLIANCE MEMBER

    When properly adjusted, the electric choke works very well and there is no need to mess with a hand choke. During shipping and handling the carb can be jostled and banged around, altering float levels, as were mine.
    Why do you persist into wanting to get into changing jets and metering rods? They don't even come into the picture at an idle throttle setting and speed!
    As several others have stated the carb comes with a very comprehensive manual that can get the carb, and you, back right. USE IT!!!!!!
     
  14. Conor Barclay
    Joined: Aug 13, 2019
    Posts: 6

    Conor Barclay

    I'm planning on adjusting the metering and jets after I get it to start and idle cold. Because It runs perfectly warm I'm assuming that the floats are ok. And I have the high idle, regular idle and mixture screws properly adjusted I'm gonna adjust the choke. I was assuming it was fine because it's a new carb, but everything is leading me to believe the choke is coming off to early.
     
  15. Truck64
    Joined: Oct 18, 2015
    Posts: 3,573

    Truck64
    Member
    from Ioway

    It doesn't hurt to check. The bench setting of the float is just that, a ballpark adjustment, it should be close enough to start and then it is finalized on the engine it is installed on.

    Fuel pumps vary in pressure output and flow, different line sizes etc, so once the carburetor is installed on YOUR engine, it needs to be checked. You've already measured the fuel pump pressure to make sure it's not out of spec. Nod your head "Yes..."

    Then raise or lower the float as required to get the fuel level in the bowl to specification. Do this on level ground, engine warmed up. Maybe let it idle for a minute or two, and shut the engine off. The carburetor is calibrated for a very specific fuel height, maybe +/- 1/32", that's what really counts, not the float height as such.

    Holley has an ingenious method of setting float height/fuel height on the fly using an external screw and jamnut with a sight glass or weep hole. Other carbs require some level of disassembly but this is probably the most important carb adjustment because it affects everything else. If fuel level is too high it may flood or cause fouling, too low it will run lean and low on power, etc. Do it right the first time is way easier!
     
  16. Happydaze
    Joined: Aug 21, 2009
    Posts: 796

    Happydaze
    ALLIANCE MEMBER

    Makes total sense to me, but.... is there an Edelbrock spec for fuel level, as in actually measuring the fuel level in the bowl? I don't recall anything but the high and low measurements of the float itself to the gasket surface. But I've never had an issue (that I'm aware of!) just measuring the float height as mentioned.

    Chris

    Chris
     
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  17. pprather
    Joined: Jan 10, 2007
    Posts: 1,357

    pprather
    Member

    I think Truck 64 is talking about setting float on a Holley carb. Most of that info does not apply to the Edelbrock in OP.
    Follow the Edelbrock manual for all needed procedures.

    Phil
     
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  18. deathrowdave
    Joined: May 27, 2014
    Posts: 1,777

    deathrowdave
    ALLIANCE MEMBER
    from NKy

    Does Edelbrock use 12v or stator voltage at the choke heater ? I have never owed an electric choke carb .
     
  19. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,193

    dirty old man
    ALLIANCE MEMBER

    The electric choke uses current flow thru resistance to heat a coil which opens the choke as it expands. Watts are what it needs to heat the coil, and I doubt the coil cares whether the voltage is 12V or 6V. or where it comes from.
     
  20. Truck64
    Joined: Oct 18, 2015
    Posts: 3,573

    Truck64
    Member
    from Ioway

    Somewhere Edelbrock has to have a spec sheet
    I used Holley carbs as an example of a good engineering design for setting a float.

    I figure he's smart enough to look in the Edelbrock literature for an Edelbrock carburetor. I'm quite certain Edelbrock has a specification somewhere for fuel height. They have to, the entire carburetor is designed and calibrated around it, which was my point. Sorry for any confusion. Thanks.

    Ted
     
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  21. Edelbrock has a series of tuning videos on YouTube that help explain the tuning procedures outlined in their manual- they really are a very simple carb to tune and adjust- They are however very much affected by fuel pressure if it’s too high( over 6 psi ) I too have had new ones that required float height adjustment - not difficult to do


    Sent from my iPhone using The H.A.M.B. mobile app
     
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  22. You are correct, sir. But what I believe you're thinking of is a choke pull-off or choke vacuum break.

    The choke unloader adjustment is for the mechanism or linkage that holds the choke valve open at wide open throttle. The only time it comes into play really is when trying to start a flooded engine. You want to hold the throttle wide open while cranking and attempting to clear the flooded condition. But if the choke valve is closed while cranking it will keep adding more fuel and less air into the cylinders of an engine that's already suffering from being too rich.

    The choke unloader doesn't get a lot of use under normal conditions and as a result the adjustment is seldom checked, even during a carb rebuild. Which usually isn't an issue unless someone else has "adjusted" it in a failed attempt to correct another problem.
     
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