fuel pump draining back to tank

Discussion in 'Fuel and Air Systems' started by KJoeZ61, Jul 20, 2018.

  1. KJoeZ61

    KJoeZ61 Well-Known Member

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    I bought a cool carb kit last weekend at Carlisle for my Quick Fuel. So I went to install it today and noticed when I disconnected the fuel line at the filter it was dry. It's been hard starting when sitting for several days or longer. I replaced the fuel pump for the same reason last year. It's a Delphi from AutoZone. Anyone have a better place to buy a stock fuel pump?

    The cool carb kit. Only had it on and drove for about 45 minutes and restarted without a sputter. So far I think it's a big improvement over the Edelbrock insulator gasket I had on. Idled much better at stops, so far I'm impressed. Blaming both of the issues on the ethanol. Even before I put the Edelbrock insulator on and just had a gasket, you could see the fuel boiling in the carb.
     
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    • billccm

      billccm Well-Known Member

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      Did you buy the thick, or standard?
      Interested if this works for you.
       
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      • 70aarcuda

        70aarcuda Master Hoader of SBM FABO Gold Member

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        not the ethanol...gasoline is blended for fuel injection...not carbs...so i evaporates fast...
         
      • KJoeZ61

        KJoeZ61 Well-Known Member

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        Bought the thin one because I have a height issue. This includes the base plate and spacer and 3 gaskets. All in all it only goes up about 1/2", but I see a noticeable difference. Don't know about the blend, but this summer in Pennsylvania the gas sucks for old school cars, and I still blame the enathol!

        My question was "better fuel pump recomandations?"
         
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        • AJ/FormS

          AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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          water don't run uphill, and neither does gas.
          There is only one way for the gas to actually return to the tank, and that is if the tank is not venting, and develops a vacuum.
          More likely is that the pump is sucking air.
          Or that after the engine is shut off, the fuel is boiling in the line, when the float drops..... due to it boiling in the bowl. Then possibly the vapor pressure in the hot tank, forces fuel up the line and it boils in the pump, and the fumes escape thru the now continuously open float-valve.... Next morning the tank has cooled off, the vapor contracted,and it pulled the fuel back.
          IDK I like the story.
          Check your venting.
           
          Last edited: Jul 20, 2018
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          • toolmanmike

            toolmanmike FABO Staff Staff Member FABO Gold Member

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            A big problem with AFB/AVS/Edelbrock carbs. I bought a insulator as well. I have been eyeing them at the Nats for a few years. Like the owner said, Edelbrocks have a very small float bowl that sits right over the intake. It's very easy to boil/vaporize the fuel during a hot soak.
             
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            • BigBlockMopar

              BigBlockMopar BigBlockMember

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              A simple electric fuel pump takes care of empty bowls in about a second.
              Having cooler gasoline is a good thing, and an insulating spacer always helps with that.
               
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              • mderoy340

                mderoy340 Well-Known Member

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                Your check valves are leaking. This is what I use with a dead head regulator and 3/8 fuel line from the tank for steady 1/4 mile WOT flow. Summit regulator is set to 6.5 psi OOTB.
                Carter Strip Super Mechanical Fuel Pumps M6270
                Carter Strip Super Mechanical Fuel Pumps M6270
                 
              • 69hemibeep

                69hemibeep Well-Known Member

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                Here is my non scientific observation and poll. I have been working on quite a few mopars at my place over the last few years and noticed the cars with Carter or Edelbrock carb's after running stink up the garage for a couple days due to evaporation and are hard to start due to dry carb's after a few days. The cars with Holley carb's don't smell and restart easy weeks later. So at a car show with a number of Mopar owners there I did a survey and found the same results.
                 
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                • KJoeZ61

                  KJoeZ61 Well-Known Member

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                  That's actually what I was thinking. I have a Quick Fuel HR-650 on it and it's great, but I was told no more than 6psi of fuel pressure. So if I go with the Carter I would need a regulator, right?
                   
                • mderoy340

                  mderoy340 Well-Known Member

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                  Yes. Run the regulator as is, it is set at 6.5 from the factory. I run a demon and QF with this regulator and both of my cars run great.
                   
                • TrailBeast

                  TrailBeast Slightly Twisted Member

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                  One thing to keep in mind is that a lot of people talk about the fuel getting or running back to the tank.
                  The only fuel that runs back is what is in the lines, as it is not physically possible for the fuel in the carb bowls to run back.
                  Evaporation is what empties bowls.

                  On another note, I know a lot of people don't like the thought of running an electric pump.
                  The electric IS the way to have instant fuel in the carb and instant starts.
                  After the electric my car starts pretty much before you can get your hand off the key.

                  Here's a video to prove it.:D
                  This is first thing in the morning and the car had not been started since early the day before.
                  (Neighbors mower was running in the background)
                  www.letsgocomputers.com/dart/morningfire.avi
                   
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                  • 70aarcuda

                    70aarcuda Master Hoader of SBM FABO Gold Member

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                    the eddy/carter carb accelerator pump well does not extent itself down to the bottom of the fuel bowl so once the gas evaporate below the well....you have no shot to start the car....the holley accelerator pump is on the bottom of the bowl and there for will provide a shot of gas longer....

                    my e85 carbs on the race car sit for month and still squirt gas to start the engine....that is 85% ethanol...
                     
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                    • KJoeZ61

                      KJoeZ61 Well-Known Member

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                      it was dry even in the filter.

                      IMG_0956 (002).jpg
                       
                    • KJoeZ61

                      KJoeZ61 Well-Known Member

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                      Has anyone used the Edelbrock 1720? Its supposed to be set for 6psi.
                       
                    • oldkimmer

                      oldkimmer Well-Known Member

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                      The filter is not always full, it can have almost no fuel to being full when running, it just the way the system works. Kim