6lb pump blowing out carb?

Fuel and Air Systems

  1. 70DusterBob

    70DusterBob Well-Known Member

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    After we got the entire engine running for the first time, it made it about 15 miles before it started flooding. Then after I rebuilt the carb, it made it about 12 miles, then started flooding. I don't want to rebuild everything in the carb again. My friend suggested that the 6lb fuel pressure may be blowing out my needles and seats. I tried adjusting them and that had no effect on the fuel level. It is an eddy fuel pump. I can get the #s for you, but it is a 6lb pump. I'm thinking I need a regulator, but then what is the point in having a eddy 6lb fuel pump, you know?

    I use a Holley 750, then tried my 650. On the 650 it started to seep around the primary inlet junction, and at the needle and seat nut and bolt. That tells me it is probably too much pressure.

    What are my options and is getting a regulator better than going with a stock pump?
     
  2. toolmanmike

    toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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    What carb? Holley's can handle 6#. Carter/Edelbrock's like 4-4 1/2#.
     
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    • 70DusterBob

      70DusterBob Well-Known Member

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      That's weird. It is a Holley 750, DP, I'm not sure why it would blow out twice like this. But rebuilding it and putting it back together seems like a waste of time until I know what is causing it.

      The Holley 650 DP had been sitting dry for a long time, maybe 4-5 years, so I can see it leaking where the primary fuel inlet is and the needle and seat bolt. But this 750 has me stumped.

      I do have rust in my fuel line, I got a clear glass fuel filter so I could see if anything is accumulating, nothing noticeable yet. Only has 12 miles on it though because it flooded again and died.
       
    • Bulldozer

      Bulldozer free ice cream sandwiches

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      Eddie's are happy at 5 to 5 1/2 lbs. make sure your floats are set right... 7/16 and 15/16 drop. your pump may be pushing more than 6. either put a regulator on it or go back to a factory pump.
       
    • toolmanmike

      toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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      Double check the float levels. Double check the fuel filter. They can pass the finest of rust particles. Take it off and pour the fuel into a bowl to see how dirty it is. I would install a pressure regulator just in case.
       
    • 70DusterBob

      70DusterBob Well-Known Member

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      I forgot to mention, I tried adjusting the floats to no avail. I will put new needle and seats in it, then put a steel covered fuel filter.

      If I knock the press down to say 4# will I still get the additional flow when needed at top end?
       
    • toolmanmike

      toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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      Shouldn't be a problem.
       
    • 70DusterBob

      70DusterBob Well-Known Member

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      Cool. Thanks.
       
    • Daves69

      Daves69 Well-Known Member

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      How do you know the pump is only pushing 6? Do you have a vacuum / fuel pressure gauge you can test with?
      Primary side only flooding or both? If just one, swap the needle and seat. Prove it follows. If it don't follow, maybe a weak float.
       
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      • 70DusterBob

        70DusterBob Well-Known Member

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        It says 6# on the spec sheet. Yes I do think it is pushing more. Both front and rear run good for about 15 miles then the floats can not adjust to stop the flow.

        Makes sense that it's pushing more. I bet you nailed it!
         
      • RustyRatRod

        RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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        I've had Holleys handle 10 PSI before. If it's having trouble with 6 PSI, something else is wrong, like maybe bad or dirty needle and seat.
         
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        • TrailBeast

          TrailBeast AKA Mopars4us on Youtube

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          After 15 or even 5 miles it floods says there is junk in the fuel causing it.
          Betcha 10 bucks if you pull the primary bowl off you'll find a bunch of crap settled in it and your accelerator pump.
           
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          • 70DusterBob

            70DusterBob Well-Known Member

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            We'll see. I planned on pulling both bowls to check them out for debri and to re-set the floats. If you are right, how can I get the crap out of my line? It sat for about a year. Not sure if it is rust or varnish breaking loose and plugging the needles/seats up, but you could be right. I am on it.

            I will work on it tomorrow and see what's up.
             
          • 70DusterBob

            70DusterBob Well-Known Member

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            Well, I just couldn't dam wait. There's enough crap in there to start a bull chip slingin' contest. lol Most of it was in the fuel, like when I dumped it out, into a pan. Tons of chunks of junk. Minor chunks of junk in the bowl spells stuck floats. The float was at the right level.

            I guess I could just buy a bucket of filters, run it about 5 min and change it x 10 or something. I don't know how to get the rust out, didn't see any varnish, but that would be hard to see now. So anyway, I will think of ways to filter the line several times until the junk is out. That glass filter apparently doesn't stop chunks. Went right through it.
             
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            • toolmanmike

              toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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              One of the first things I did for my 66 Dart (and one of the best things I did) is I bought a new tank,sender,pump, and lines. Replaced them all and in 13 years I haven't had any rust issues. A whole bucket of fuel filters won't fix the cause of your problem.
               
            • yellow rose

              yellow rose Master Of Insanity

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              The issue is going to be whatever is in the tank, is going to keep flaking off. Most likely forever.


              I used some stuff to seal and coat several dirt bike tanks to save them. It worked but it was a ton of work. I can’t imagine doing it to an automotive fuel tank, but I know guys do it.

              Thats kind of your options...try and seal your tank, or buy a new one. Otherwise, you’ll fight this for a long time.
               
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              • 70DusterBob

                70DusterBob Well-Known Member

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                I know it won't fix the cause, I would like to get the Duster out of here and into storage where it cannot be stolen. I'm on the outskirts of the city right now. Brought it here to work on some issues and now I'm kinda stuck. I think if I filtered it say 10 times that I could make the 25 mile drive to storage. The car sat for over a year while the rust accumulated. I'm thinkin if I filter it out like 10 filters I could get the majority of the buildup out. Believe me, I will look into a SS line. If it's not too much I may just swap it here. Heck the last time I looked they were just over $100, 10 Filters run a good $50-60!

                I appreciate your input. I'm getting desperate to get 'er out of here and it's messin' with my judgement.
                 
              • gm1236

                gm1236 Well-Known Member

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                I just replaced the tank in my ‘75 duster. This car has not been driven much in the last 10 years and the entire inside of the tank was rusty, very rusty. It had a steel inline filter, regular cheap one you’d get at a parts store. It was so clogged with rust I could barely blow thought it, but the car ran fine. The filter was good enough to keep the rust from getting into the carb. I still plan on taking the carb apart and cleaning it out. It’s a Holley 4150 and it ran ok with 9# at idle. I will have an new eddy pump on it this weekend and hopefully it will be around 6#.
                 
              • 70DusterBob

                70DusterBob Well-Known Member

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                I had the tank boiled and cleaned, then seal coated about maybe 10 years ago. Do you think it is holding up? Could just be the line.
                 
              • 70DusterBob

                70DusterBob Well-Known Member

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              • 70DusterBob

                70DusterBob Well-Known Member

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              • toolmanmike

                toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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                Before you pull the trigger on stainless, it took 50 years for your original steel lines to fail.
                 
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                • RustyRatRod

                  RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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                  What I would do if you cannot afford another tank......or you are not in a position to do the job yet is, get a gas can and run a hose from it to the fuel pump inlet. Clean gas. Then you can drive the car into storage like you are wanting to do. Of course, you'll need a new filter and you'll need to repair the carburetor.
                   
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                  • Mattax

                    Mattax Just the facts, ma'am FABO Gold Member

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                    That would be the maximum pressure when flow is stalled (valve shut).
                    If accurate spec. the pump alone can never develop more than 6 psi. When you see how the pump works, it will make sense.

                    But now you've discovered its not the pump, but garbage coming through. So lets go there.
                    Take a real close look at the garbage. See what it looks like with some magnification. See what it feels like. Put some photos up if you can. Lets see try to figure out if what is coming through is the sealer, rust, or what.

                    Anything big should be stopped by the filter in the tank. I've seen two types of 'socks' sold. If given a choice, use the one that is cylindrical.
                    A paper filter will probably pass the least trash, even the smallest stuff. Chrysler used both semi-clear plastic and metal housing. So I don't worry about that.
                    Finally, you could install the sintered bronze filters some Holley carbs come with. Lots of guys remove them in fear of reducing flow. So maybe someone has a set in their collection they will gladly donate to your cause.
                     
                  • 70DusterBob

                    70DusterBob Well-Known Member

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                    Yeah, that did cross my mind. I won't be here in 50 years, but hopefully my car will. I think for now I can get the regular steel easier to bend if I need to as well, and be happy.

                    Thanks
                     
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