Edelbrock 1406 rich!

Discussion in 'Troubleshooting & Diagnosis' started by Thomasg, Nov 30, 2017.

  1. Thomasg

    Thomasg New Member

    Sep 30, 2017
    Hey guys I’m having trouble getting my Edelbrock 1406 carb tuned up. Rebuilt 383 stroker. I adjusted the idle mixture screws and there’s a chance I could’ve done them wrong. Basically my ‘75 Camaro won’t idle when it’s cold, unless I open the butterflies on the choke. Once it is warm it runs better, but until then I keep a screwdriver in the choke linkage. I gave the car some throttle to help it warm up and the car left a couple black exhaust soot marks on my driveway. Could this be a timing issue or does the edelbrock need a rebuild? Also it doesn’t seem that the choke disengages when the car warms up
  2. Coadster32

    Coadster32 Veteran Member Lifetime Gold Member

    Oct 2, 2013
    There is a procedure to follow in the book for choke adjusting and operation. It'll also tell you about the screws as well. Might be too much line pressure flooding a bit at low rpm, and the cold motor can't handle it. Timing is another thing as well, but seeing how it's a cold starting idle issue, I'd tend to the carb first.
  3. John Wright

    John Wright Veteran Member Lifetime Gold Member

    Aug 9, 2002
    Rustburg, Va
    Edelbrock carbs are pressure sensitive, check the fuel pressure and make sure you keep it around 5-7psi. Get it warmed up and running at operating temps first, then you can always work on the cold start tune later. To adjust the choke, there are screws around the perimeter of coil that hold the bi-metal coil in place, just loosen them and turn the coil until the choke stays (straight up and down) open for you. Just pat the gas and keep it running until it warms up enough to run on it's own. Then like I said, you can work on the cold start issue later. If you have a vacuum gauge, you can adjust the mixture screws for max vacuum at idle and that will get you close enough to get started with tuning.
  4. cadillac_al

    cadillac_al Veteran Member

    Apr 22, 2015
    The 1406 comes jetted quite lean. You must have too much fuel pressure (never happened to me) or an incorrect float setting.
  5. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

    Nov 4, 2004
    Ringgold, GA
    The little experience I have with that carb has been mentioned above. I kept fuel no more than 5 psi, plus check float height, they're known to be off.
  6. Rdobbs1977

    Rdobbs1977 Huge Guns N Roses Fan

    Dec 1, 2014
    I've gotten pretty experienced with the eddy performer carbs. good news is they're not complicated. Yes check floats, should be 7/16" clearance. Lot of people use a drill bit to check, i've found i've got a set of feeler gauges that work when putting my caliper on there to determine 7/16. Yes, check your fuel pressure too. Eddies i've found like around the 4psi range.

    Don't run chokes on any of my carbs. Every carb i've ever gotten, i've removed the flap and linkages.

    Your black smoke could be a result of your IMS screws not being set right. Typically 1.5 turns out gets you pretty close. Then as one guy said, use a vac gauge or your ears or your RPM gauge to fine tune it. But in all honesty you could set it at 1.5 and be done with it.
  7. Cardinal

    Cardinal Veteran Member Lifetime Gold Member

    Jun 22, 2003
    Endicott, NY
    BEFORE YOU DO ANYTHING, THEE #1 problem with Edelbrock carbs is that the float drop and height are NOT set properly at the factory! Go to the Edelbrock website, get the specs (and how to set them), and then set them.

    #2 What intake are you running? We have a Wieand Action P+ intake on my son's 83 S10 with a 350 SBC in it. From day one, it was a female dog to start, ran like crap, and awful MPG! Eventually, we got to work all day on it. We found the following:

    1. float height and drop were WRONG! Set them, truck ran better but still not running 100% like it did with a Q-Jet on it.

    2. Pulled the carb to put a 1/2" spacer in it (thinking that it might help) only to find the intake to carb gasket had a minor leak on both sides of the carb due to intake being a "universal fit" = it was wide in the back half of the intake port = Q-Jet size. Since the 1406 is a "square bore" there was a miss match between the carb and intake. I made a "goof plate" (gasket + plate + gasket), installed it, engine calmed right down and it ran like a raped ape in a banana factory! Vacuum leaks can be found by CAREFULLY spraying starting fluid around the intake and carb with the engine running. When sprayed on a leak the RPM's will pick up!

    3. Next day, it was still hard to start when cold. Spent a lot of time setting the electric choke which now still works after many years of operation.

    4. Setting idle mixture screws: Once all of the other problems have been addressed, setting idle mixture screws requires a LOT of patience and time. Engine has to be warmed up and choke off. Initial setting is from 1.5 to 2 turns out on both of them. SLOWLY turn one screw in and listen (or read a tach meter) for the engine to slow down (rpms drop). Slowly open that one back up till the rpms pick up slightly. Now adjust the other idle mixture screw in until the rpms drop them run it back until the rpms barely pick back up. Keep doing this to both screws until the engine purrs like a kitten.
  8. Thomasg

    Thomasg New Member

    Sep 30, 2017
    I will check my float level. I heard you can check it using a drill but. I’m currently running an edelbrock performer intake
  9. Thomasg

    Thomasg New Member

    Sep 30, 2017
    How did you know that you had an intake leak? Was the gasket visually wet when you pulled the carb. I’m ready to pull this carb and try a rebuild. My fuel pressure seems to be right on
  10. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

    Nov 4, 2004
    Ringgold, GA
    It's hard to visually locate a vacuum leak around the base of the carburetor, it won't be wet because it's sucking air, not fuel. If your intake is the dual pattern type that has the large (Q-jet) ports in the rear, you need to check that area for leaks. My favorite is an unlit propane solder gun, just work it around the base of the carb with engine running and you'll hear rpm's increase if you have a leak. Cardinal made his own metal plate but you can buy them also.

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