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Completely new fuel system. . .priming???

Discussion in 'Shop - Engine' started by atomicjoe23, Apr 28, 2010.

  1. atomicjoe23

    atomicjoe23 Well-Known Member

    Joined:
    Feb 2, 2008
    Location:
    Silverdale, WA
    I'm about 95% done (to my knowledge anyway) with my first complete vehicle build and I installed a 100% new fuel system (new fuel cell, fuel line, fuel filters. . .fuel cell outlet and carb inlet, mechanical fuel pump, and carb) and I'm wondering if I need to prime the fuel system to make sure that fuel is getting to the carb so that I can fire my rig up for the first time?

    If I don't need to prime it what do I need to do. . .if it were an electric fuel pump I wouldn't even be asking this question, but I'm wondering how I make sure I'm getting fuel to my carb if I'm starting with a new "dry" fuel system and a mechanical fuel pump.

    I haven't had very good luck with carbs in the past so I'm hoping you guys can help me out.

    Thanks!!!
     
  2. Wilson

    Wilson Active Member

    Joined:
    Jul 26, 2008
    Location:
    Carlsbad, CA
    You shouldn't have to prime it, normal engine cranking should start the flow of fuel to the carb (unless you've got a restriction somewhere or the pump has to pull the fuel "uphill"). It may take a few seconds depending on the layout of your fuel system. The more vertical distance between the fuel cell and the fuel pump, the longer it'll take. If the engine is ready to run, it'll start as soon as the fuel gets there. If it's not ready to run, you can check by disconnecting the fuel supply line at the carb. - just be careful not to let fuel spray everywhere......
     
  3. Sparky

    Sparky Active Member

    Joined:
    Apr 4, 2006
    Location:
    Feeniks, Aridzona
    You can disconnect the ignition coil and pull the spark plugs and crank it. That will let the engine spin faster (which will also help prime the oiling system) until you get fuel into the carb. You will know that you have fuel in the carb when you start getting a spray out of the accelerator pump.

    Alternately, I've also just poured a tiny amount of fuel into the carb to get it to fire briefly. Be careful of backfiring though! Don't be looking down into the carb while cranking!
     
  4. atomicjoe23

    atomicjoe23 Well-Known Member

    Joined:
    Feb 2, 2008
    Location:
    Silverdale, WA
    Thanks guys!

    I'm gonna prime the oiling system before I try to start it (I've already added the zinc treatment for my flat tappet cam) and the fuel cell and the carb are basically level with each other with the fuel pump being below the level of the bottom of the fuel cell.

    Thanks again!
     

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