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  • Fuel System: help with edelbrock 1405

    Hi all, i've got a 64 289 with a 1405 on it, it runs but is very rich, black smoke, plugs are black & sooty. i've read a few old posts on here & it sounds like the carb is to big. It was on the car when when i bought it, & i'd to use it
    I was wondering if a jet change would help? It has a mechanical fuel pump, i've checked fuel pressure about 5 psi, even throttled it back to 4 psi by choking off the rubber line with a small clamp before the gauge, made no difference. Any ideas other then buying a 1403?




























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  • #2
    rated at 600 cfm, this carb should be okay for a 289. First I would check to see if the choke is fully open, and heat riser is fully open...then double check idle mixture screw setting, although if it runs rich through the rpm spectrum the idle air mixture is going to do squat. If one of these are not the cause, I would pull the top off of the carb and check the float setting and make sure the jet size and metering rods are what the factory installed. Hopefully one of these will fix you up as these carbs are fairly simple and are set up to run on small(ish) v-8`s right out of the box. I chose a 500 cfm for my car because I wanted really crisp throttle response off idle and good economy, but can`t think of why a 600 wouldn`t work...many others I`m sure have used this carb. good luck, junior
    sigpic
    1954 C5 Hamilton car.

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    • #3
      Originally posted by junior View Post
      rated at 600 cfm, this carb should be okay for a 289. First I would check to see if the choke is fully open, and heat riser is fully open...then double check idle mixture screw setting, although if it runs rich through the rpm spectrum the idle air mixture is going to do squat. If one of these are not the cause, I would pull the top off of the carb and check the float setting and make sure the jet size and metering rods are what the factory installed. Hopefully one of these will fix you up as these carbs are fairly simple and are set up to run on small(ish) v-8`s right out of the box. I chose a 500 cfm for my car because I wanted really crisp throttle response off idle and good economy, but can`t think of why a 600 wouldn`t work...many others I`m sure have used this carb. good luck, junior
      Heed why junior says before you ashcan the carb. I ran that same carb on a 305 SBC and it ran very well. Once you have checked everything out, as per junior, either open up your instruction if you have them or download them from the Edelbrock site. In them you will find a very nice chart of jet and spring combinations. Take out your jets/springs, see what you have and go from there.

      It's a little large but it should be fine on your engine when it's correctly configured.

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      • #4
        I agree. The carb "size" is not the problem.
        Choke adjustment would be #1 on my list of suspects.
        A quick Google search suggests edelbrock 1405 has a manual choke.
        And the "air valve" secondary would try real hard to keep it from being a "big" carb unless the engine was taking big enough breaths to need it.

        Do you recall Which post said it was that linked carb size to A/F ratio ?

        regards,

        Dan T

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        • #5
          While the carburetor size isn't ideal, (yes, the 500 version is much better suited to the engine), I agree, seems you have most likely a misadjustment some where. Look on the Edelbrock web site, you should be able to find their adjustment information for all adjustments within the carburetor. Including the proper jets and metering rods, rod return springs, float height, etc., etc.

          Mike

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          • #6
            The carburetor cfm rating has nothing to do with the A/F ratio. The engine only uses what air the throttle will allow, and is also limited to the displacement of the engine.
            If you are running too rich for the air flow you are using, then it needs less fuel. To accomplish that requires either a jet change, a metering rod change or the spring rate that changes the rate of change on the metering rod vacuum piston. Possibly all three. The 1840 is the edelbrock calibration kit for an 1405 carb, and has all the parts you will need
            Bez Auto Alchemy
            573-318-8948
            http://bezautoalchemy.com


            "Don't believe every internet quote" Abe Lincoln

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            • #7
              You definitely need to change the jetting. The 1405 is jetted larger than the electric choke 1406. 100 vs 098 and narrower metering rods 70 vs 75. If you drop the primary and secondary to 1406 levels 098 and a 75/47 rod it would be a good place to start. From there you may want to go leaner but I'll wager that moving the jets to 1406 levels will solve your immediate problem.

              ErnieR

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              • #8
                I have ran both 500 and 600 AFB clones (Edelbrock) and, when properly set up, its hard to tell the difference between the two, in terms of performance & MPG. First, check the floats and inlet valves (free & easy). If that doesn't reveal anything, play with the tuning; a "Strip Kit" comes with an assortment of rods, springs, jets, and a manual. With it, you can have fun setting yours up the way you prefer; for performance, MPG, of a compromise between both.

                No matter how fine tuned, it is still 1960s technology, with the same quirks as back then: poor MPG, excessive cranking on hot restarts, and a need to feather the pedal/run at high RPM till it smooths out, a minute or two after a hot restart. It is what it is though, and usually runs reasonably well on a Stude V8, when set up right.

                I say "usually" above, because some of the recent ones come out of the box with a high idle that some tuners have had lots of trouble bringing down. A search of the archives here will reveal more about that problem some have experenced.
                Last edited by JoeHall; 12-21-2014, 06:29 PM.

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