Fuel/Air mix pumps? What are the options?

Discussion in 'Stove Forum' started by montanafan, Nov 4, 2019.

  1. montanafan United States

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    Hello,

    I have had experience with several liquid fuel pumps that have the fuel/air mix capability. Namely the Soto Muka, Snow Peak WG, Coleman Apex II.

    All of these pumps are quite particular in their history:

    Coleman Apex II pump was prone to cracks around the brass fitting.

    Snow Peak WG pump was recalled via CPSP.

    Muka (Stormbreaker) Pump is a overly complicated heavy beast. Mine worked fine, required a TON of pumping to make work well.

    Question is??? Are there any other options out there for stove pumps that had a fuel/air mix capability? The ability to not have to prime a WG stove is cool, but the above pumps showed that is was a complicated task.

    Edit: Stand alone pumps. Not integrated pumps like Coleman successfully managed with their stoves.

    Just curious,
    M
     
  2. geeves

    geeves New Zealand Subscriber

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    The part that mixes air and fuel is only the design of the pipe at the end with an elbow of some sort sitting in the fuel and a second inlet above the fuel. The size of the 2 inlets controls the mixture. In theory it should be possible to modify any pump to handle an air fuel mix. I will have to try this in practice soon as my apex pump is starting to crack
     
  3. montanafan United States

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    I don't think so. Both pumps, if I recall used dual pickups. One air. One with an elbow in the fuel. They were controlled with a "start" and "run" position switch. The Soto, used a dual path valve for air and fuel separately. There are tear down pics on the forums.

    The start position used fuel/air mix. The run position was 100% fuel. Maybe....I think.
     
  4. ArchMc

    ArchMc SotM Winner Subscriber

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    Yes, you are correct: 'start' uses a fuel/air mix; 'run' is liquid fuel only.

    That's why you have to pump it up again after switching to 'run'. The mist that is produced by 'start' uses up a bunch of your air.

    ....Arch
     
  5. geeves

    geeves New Zealand Subscriber

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    Dont think the apex has anything like that
     
  6. ArchMc

    ArchMc SotM Winner Subscriber

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    Just dug out my Apex II to be sure, and @geeves is right. So I dug out the instructions. (I've started this stove before, but have never used it in the field.) The instructions say (I'm paraphrasing):

    Pump it 50 full strokes.
    Open the valve on the stove all the way.
    Hold a lighted match to the burner and open the valve on the pump.
    Once it lights, immediately give the pump another 10-20 strokes.
    After warm-up, use the valve on the stove body to adjust flame.


    So instead of using stored pressure from the tank to form the startup mist, the Apex II makes you provide this extra pressure manually after lighting.

    Since the Coleman pump doesn't have the fuel/air mix capability, this suggests you may be able to use any pump you can adapt to fit, such as an MSR or a Primus pump.

    Obviously, do this in a safe place, with fire suppression handy.

    ~Also, adding a non-Apex pump makes this a frankenstove, so you, personally, must assume all risk.~

    Let us know how it works.

    ....Arch
     
  7. theyellowdog

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    I don't have one anymore, but I think the apex also has a small hole in the elbow of the air tube to help the fuel mix at start up.
     
  8. ArchMc

    ArchMc SotM Winner Subscriber

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    The hole in the elbow is actually the fuel pick up. (The elbow sits on the bottom of the tank when it's lying on its side.) One tube from the elbow connects to the valve on the pump. The other rises up above the fuel level to allow pressurized air in.

    So I take back part of what I said before. To use a non-Apex II pump, you would have to incorporate something equivalent to this elbow-with-a-hole gizmo into the fuel pickup tube. The same caveats apply.

    This is a fair amount of hassle just to get around priming the stove.

    ....Arch
     
  9. montanafan United States

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    yep, Apex pump was different from my Snow Peak pump. IMG_20190826_210321286.jpg