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electric fuel pump and vaporlock

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  • Fuel System: electric fuel pump and vaporlock

    Is there an advantage to using electric fuel pump to help with vapor lock. Added pressure make a difference? does it push fuel through mechanical pump. In the 45+ years I've owned Studebakers, vapor lock hasn't been much of an issue. I have both 6 and 12 volt cars and truck.

  • #2
    Yes. Remember those high school physics classes ?
    Just like the coolant system, more pressure, the higher the boiling point.
    Not "quite" the same with "higher pressure" in the fuel system, but the very same principal. With the liquid (fuel) more densely packed (pressure), the less chance of turning into a vapor before it gets to the carburetor jets.



    • #3
      Thank you Mike. I wasn't smart nuf to physics class. I appreciate the encouragement.


      • #4
        I have a 6V pump and pressure regulator I took of my recently acquired 53 Commander for sale for $75. I prefer all my vehicles stock so I’m installing the correct fuel pump.


        • #5
          I installed an electric fuel pump with a toggle switch on my '55 President to help with the vapor lock problems I had now and then. The first time I drove it on a hot day and the engine started to buck due to vapor lock, I reached under the dash and flipped the toggle switch. The engine smoothed right out. I was delighted. I expect you will have similar results.
          Ed Sallia
          Dundee, OR

          Sol Lucet Omnibus


          • #6
            Agree with Eddie, but I think you might want to opt for a mechanical pump rather than a vane type as the former is self-priming. And be sure to put the filter between tank and pump. I've be wiring to acc. circuit so I can switch to acc to prime the pump and carb if car has been sitting for a while.


            • #7
              I wish I knew the true definition of what a vapor lock is. There are as many definitions as there is cures. I feel the main problem is a non functioning heat riser and the fuel is boiling in the carburetor, over flows and over fuels the engine and it dies, let the engine sit for a while the excess fuel evaporates and all is well again, no real "vapor lock" what ever that is, just over fueling. A mechanical fuel pump will pump air (vapor) or fuel with out any problems so the fuel pump can't be blamed. I tested a fuel pump with a 10 foot pickup hose into a container of solvent while standing on a ladder. It took about 3 - 5 pumps and the fuel (solvent) was squirting out at least 6 feet with no priming.


              • #8
                True vapor lock is where gasoline vapor forms in the suction line. Sure the pump will pump vapor, but the vapor bubble keeps expanding, and all that comes out of the pump is vapor, upon which the engine will not run. The other condition you describe is called "percolation". Fuel boils in the carb bowl, and floods the intake manifold. And you can have both happen at the same time. You crank to clear the flooded engine, it starts and runs briefly, and then quits for lack of fuel.

                If Studebaker were building cars today, they would have electric fuel pumps, assuredly.
                Gord Richmond, within Weasel range of the Alberta Badlands


                • #9
                  Commander Eddie's experience is an exact parallel to my own.
                  My 55 President (WCFB cleaned and kitted last year, Carter fuel pump, unknown age) almost never needs a pressure boost from the inline electric pump on the frame just forward of the fuel tank.
                  On a 95 degree day when you pull out into traffic and the plant starts to falter, a few seconds of electric pump keeps me accelerating and the Hondas/Toyotas out of my trunk.
                  Just my experience.


                  • #10

                    1. A mechanical (only) fuel pump attached to a 180 degree engine having a similar temperature air blowing across it as it attempts to pump (draw) fuel blends primarily configured for fuel injection engines that are prone to boiling,


                    2. An electric fuel pump in proximity of the likely no more than 100 degree fuel tank pushing fuel to the mechanical pump that other wise might be churning bubbles.

                    You can buy a Cube type electric pump on Ebay for as little as $15. The installation, even for a novice, is no more than an hour and a half. Junkyards are repleat with safety switches in case of a rollover or engine stall. You get the ability to prime a dry float bowl, supply cooler fuel to a percolating fuel pump or carburetor, can turn it off after priming as it has a "pass-thru" function, or..., if your mechanical pump fails you can restore the pumping of fuel at the flick of a switch.

                    The down side? You can't claim your car is COMPLETELY stock and you may be subject to ridicule for being dependent on such a foolish and frivolous device.
                    Last edited by wittsend; 07-19-2019, 05:35 PM.
                    '64 Lark Type, powered by '85 Corvette L-98 (carburetor), 700R4, - CASO to the Max.


                    • #11
                      Thank you guys very much. My Champ isn't as much a problem as my 50 Hudson. I can be cruising along the interstate at 65-70 and accelerate and it will start acting like it can't get nuf fuel. Traffic is a real problem. If it sets for a few minutes it won't fire at all. I keep a gallon of water to pour on the fuel and carb at float bowl. Recently, been carrying 12 volt battery and cables. I can't afford a jump box. Starter isn't dragging after grinding for a minute or 2 battery has a bit less power. I blame it on crappy fuel. My Dad drove both Studebakers and Hudsons back when and He never mentioned that kind a problem.
                      anyway thank you very much,