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  • Fuel System: Carburetor Conundrum

    First, the backstory: Six years ago I bought a new Edelbrock 1403 off of Ebay. A few months later, after getting a spiffy Jeff Rice converted intake manifold, I made the swap...only to discover that the carb I bought was NOT a 1403 but a 1406. Stupid on my part and then too late to return it. So, I bought a new 1403 from Summit. Put it on the car and it ran great. The 1406 went back in the carton and on the shelf. When I decided to pull the old motor in favor of a rebuilt full-flow, the 1403 was pulled and sat covered up on the shelf for some two years.

    Fast forward to now: Finally get the new motor and tranny installed, put on the 1403 and started up the motor. Could not get it to run smooth, could not get it timed...thought my problem was ignition related. Hmm, maybe the 1403 was gunked up/dried out, etc... so, I swapped it with the 1406 that had been sitting there and, by golly, the car ran great (after setting the timing, idele mixture, etc.).

    So, knowing that the 1403 is a better match for the stock 289, I took it in to "The Carburetor Shop", a well-known carb specialist in St. Paul and had them go through it (to the tune of $170).

    Got back home, took off the 1406 and put on the 1403. Car ran like crap. Was getting too much fuel and only one of the idle air mixture screws would effect any change.

    So, put the 1406 back on...car runs super. Returned to The Carburetor Shop with the 1403. Explained what was going on and he gives me one of his 1403s that he said he'd completely rebuilt.

    Got home, put it on...car runs like crap...same as before but now none of the idle mixture screws effect any change. Fuel going into the motor like its the dad-blamed Alaskan Pipeline (okay, a little embellishment there). Tapping on the carb was ineffective. This morning I put the 1406 back on...runs as it should.

    Questions: Am I missing something here? Is there some critical difference between the 1403 and 1406 that would cause this? Am I just the unluckiest carburetor buyer of all time?

    Appreciate any thoughts on this.
    sigpic
    Bob Shaw
    Rush City, Minnesota
    1960 Hawk - www.northstarstudebakers.com
    "The farther I go, the behinder I get."


  • #2
    That is just weird Bob. About the only thing I can think of that could make TWO supposedly "Good" Carbs. run poorly is something in the installation, like the Ported/non-ported Vacuum Advance tubes, what about the gaskets you are using, same as the 1406? Do they match the Venturi (sp) size? No gasket leaks? Is there power on the Auto. Choke wire?
    StudeRich
    Second Generation Stude Driver,
    Proud '54 Starliner Owner
    SDC Member Since 1967

    Comment


    • #3
      If I have this straight:

      1406 runs great, took it off put on 1403 and runs like cr@p

      put on 1406 runs great , repaired 1403 runs like cr@p

      put on 1406 runs great, repaired 1403 runs like cr@p

      put on 1406 runs great.

      Unless you like changing carbs I note a pattern here and I'm noticing a definition of insanity too.

      In any case, Bob I'm kidding , of course, but why not just leave the 1406 on and do another job on the list.

      Bob

      Comment


      • #4
        Originally posted by StudeRich View Post
        That is just weird Bob. About the only thing I can think of that could make TWO supposedly "Good" Carbs. run poorly is something in the installation, like the Ported/non-ported Vacuum Advance tubes, what about the gaskets you are using, same as the 1406? Do they match the Venturi (sp) size? No gasket leaks? Is there power on the Auto. Choke wire?
        Rich is probably correct about this. If the 1403 worked well on the previous engine...the problem must be in the install on the new engine. Especially since once You installed the 1406 the engine ran good. (No engine (issues)

        Comment


        • #5
          Originally posted by SN-60 View Post
          Rich is probably correct about this. If the 1403 worked well on the previous engine...the problem must be in the install on the new engine. Especially since once You installed the 1406 the engine ran good. (No engine (issues)
          Or the old engine was so tired it could not pump enough air for the 1406, but the rebuilt can. I can't say why the 1403 won't run right though.
          Ron Dame
          '63 Champ

          Comment


          • #6
            Bob,
            When you first put the 1403 back on the rebuilt motor after it had sat on the shelf for 2 years were the bad running symptoms THE SAME as the ones after you reinstalled the 1403 after being gone through by the carb shop? If different, I'd suspect the 1403 did get a little gummy sitting on the shelf and the rebuilder cleaned it up, but set the floats too high (and too high on his other 1403 also). The 1406 never had gas in it, so it didn't get gummy sitting around and the floats are set correctly in that one (just a guess).



            One last thought...did you add an electric fuel pump in between the old motor and the new one? You could be getting too much fuel pressure, but I would think that would also effect the 1406.
            Dick Steinkamp
            Bellingham, WA

            Comment


            • #7
              When I see a pattern such as this, it's usually a base gasket or vacuum hookup causing the problem. Turn the two carbs upside down and carefully compare the various passages. Are both carbs taking distributor, PB and PCV off the same sources?

              Also, agree, the float levels would be my second area of concern.

              jack vines
              PackardV8

              Comment


              • #8
                I's simply run the 1406. I have ran them both, and too much big deal is made about the difference between 1403 & 1406. The differences make for good hypothetical conversation, but behind the wheel any difference is negligible, and there won't be 1/2 MPG difference between the two. Also, they both have the same personality, i.e. when it comes to hot restarts, and seat of the pants feel when the pedal is pressed to the metal. I am currently running a 1406 on the wife's GT, and the only thing wrong with it is that it is a carburetor
                Just my two cents.
                Joe
                Last edited by JoeHall; 08-24-2013, 01:49 PM.

                Comment


                • #9
                  Originally posted by StudeRich View Post
                  That is just weird Bob. About the only thing I can think of that could make TWO supposedly "Good" Carbs. run poorly is something in the installation, like the Ported/non-ported Vacuum Advance tubes, what about the gaskets you are using, same as the 1406? Do they match the Venturi (sp) size? No gasket leaks? Is there power on the Auto. Choke wire?
                  Same gaskets. No leaks. I did switch between the 1403's ported and non-ported vacuum...no change...runs like crap both ways. The 1406 works great on the timed vac port, BTW. Elec choke working fine.
                  sigpic
                  Bob Shaw
                  Rush City, Minnesota
                  1960 Hawk - www.northstarstudebakers.com
                  "The farther I go, the behinder I get."

                  Comment


                  • #10
                    Originally posted by PackardV8 View Post
                    Are both carbs taking distributor, PB and PCV off the same sources?

                    jack vines
                    Yes. PCV to the front port. Rear port plugged. Dizzy: timed or manifold ports make no difference.
                    sigpic
                    Bob Shaw
                    Rush City, Minnesota
                    1960 Hawk - www.northstarstudebakers.com
                    "The farther I go, the behinder I get."

                    Comment


                    • #11
                      Dick: The symptoms were the same. One of the pre-rebuild 1403's idle air screw passages was blocked and would not register any change when adjusted. So, I removed both screws and sprayed carb cleaner per the Edelbrock book and I did get the blocked one opened (I think). However, it still exhibited the same symptoms so that's when I took it to the carb shop. Post-rebuild the same idle mixture screw that was blocked before still would not register any change when adjusted. Exchanged 1403: neither of the idle mixture screws would do a thing.

                      Yes, the old motor did have the mechanical fuel pump; new set-up is electric only with a regulator and pressure gauge that indictates a little over 3.5 psi. Whether the gauge is right is anyone's guess. 1406 runs fine on that.

                      You might have something there about float heights as that would likely be a constant between the two 1403s the carb shop rebuilt.
                      sigpic
                      Bob Shaw
                      Rush City, Minnesota
                      1960 Hawk - www.northstarstudebakers.com
                      "The farther I go, the behinder I get."

                      Comment


                      • #12
                        Originally posted by sweetolbob View Post
                        If I have this straight:

                        1406 runs great, took it off put on 1403 and runs like cr@p

                        put on 1406 runs great , repaired 1403 runs like cr@p

                        put on 1406 runs great, repaired 1403 runs like cr@p

                        put on 1406 runs great.

                        Unless you like changing carbs I note a pattern here and I'm noticing a definition of insanity too.

                        In any case, Bob I'm kidding , of course, but why not just leave the 1406 on and do another job on the list.

                        Bob
                        That's the scenario in a nutshell. Maybe I will leave the 1406 on it and move on to other things as you and others have suggested. OTOH, I have a bunch of money tied up in that 1403 and it's now personal between me and that $%&#@#!!!! carb.
                        sigpic
                        Bob Shaw
                        Rush City, Minnesota
                        1960 Hawk - www.northstarstudebakers.com
                        "The farther I go, the behinder I get."

                        Comment


                        • #13
                          I too have an Edelbrock 1403 with electric choke. Don't seem to able to keep everything adjusted. Brought it to a Mechanic Shop and they rebuilt the carb because the accelerator pump rubber had disintegrated, but it still runs like crap. It runs okay right after its been adjusted, but within a week, its running terribly again and doesn't want to start.

                          Maybe a Holly Carb Is the answer!!??
                          Laisez le bon temps roulez avec un Studebaker

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                          • #14
                            It has symptoms that sound like the secondaries are just cracked open and not fully seated. Is this possible on both 1403's ??

                            Comment


                            • #15
                              Maybe a Holly Carb Is the answer!!??
                              Only one who has not had much experience with Holley carburetors would suggest they are the answer to any carb question. That they don't even fit the intake bolt pattern is the least of the reasons a Holley on a Studebaker is not a good idea.

                              Your opinions may vary. If in favor of Holley, I've got fifty years of parts I'd love to sell.

                              jack vines

                              (lookout! here comes joe hall rushing in to praise his 'baby holley'. just remember this is the same joe hall who now is converting all the above to TBI. love ya, joe. ;>)
                              PackardV8

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