NRV Help

Discussion in 'Fettling Forum' started by BradB, Feb 1, 2020.

  1. BradB

    BradB United States Subscriber

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    My Optimus 00 continues to beat me up. In hopes that very small particles might be clogging the jet, I did multiple soakings with alcohol. Overnight I soaked the tank in acetone, and in the morning did the BB dance. I did not notice anything coming out of the tank. Today I burned the stove for about 45 minutes without a fail. It previously would extinguish after 5-10 minutes. I thought maybe I was home free. Then, while adding pressure I noticed kerosene bubbling out the pump tube. Ugh! I had previously installed a new NRV pip. When I took it apart I realized the acetone had destroyed the new pip. No problem, I put in a new pip. But the kerosene continued to leak. The pump does not rise, but kero bubbles out the pump tube. I tried a new lead gasket to no avail. I replaced the entire NRV, same result. Obviously the NRV is not sealing in the bottom of the pump tube. Any ideas how to approach this? Brad
     
  2. snwcmpr

    snwcmpr Subscriber

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    The flat is not seating properly?
    The spring is stuck?
    A burr on the inside?
     
  3. The Warrior

    The Warrior United States Subscriber

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    I thought I read somewhere that ldpe gaskets work better than the lead ones?
     
  4. snwcmpr

    snwcmpr Subscriber

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    HDPE, I have only used the old lead I have had.
    Where did you see the bubbles? That might give an idication of the location of the leak.
    In the hole, or around the lead seal. I know a small dark area at the end of a small tube.
     
  5. BradB

    BradB United States Subscriber

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    The kero comes all the way out the pump tube.
     
  6. snwcmpr

    snwcmpr Subscriber

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    Could the tube be cracked?
     
  7. BradB

    BradB United States Subscriber

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    I sure hope the tube is not cracked. Removing that might be above my pay grade.
     
  8. threedots New Zealand

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    There is a possibility that the sealing surface of the brass part that comes into contact with the pip to create the seal, may be etched or have a tiny burr(speck of a previous pip?) on the sealing edge as @snwcmpr suggests.
    I use the phosphorus head of a match and rotate it in the the hole of the brass part of the NRV to finely hone the brass lip until I get a smooth continuous edge again. Easily done if that is the problem and usually works well for me.
    When ever I service a NRV, I always do that whether it is needed or not.
     
  9. hikerduane

    hikerduane Subscriber

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    The carrier for the pip can also hang up or some pips just don't cut it.
    Duane
     
  10. Simes

    Simes Subscriber

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    The bottom of the pump tube is the last resting place of pump leather.

    The amount of sludge that can accumulate down there is suprising. Whenever I've had to venture there I've never been scrupulous with cleaning and trusted to luck that the valve seats fully, which it doesn't always.

    I've also found that some threads can be a little on the interference side of tolerance and need a little more persuasion to fully bottom out.
     
  11. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    True, down to the hardness/elasticity of the seal material and the NRV spring tension.

    Having replaced the entire NRV maybe rules out that possibility in this case though, unless its seal/spring combination is similarly afflicted.

    Only time I’ve had no reworking of an NRV succeed it’s been a cracked pump tube as @snwcmpr suggests or a failed solder joint on the end cap holding the NRV. Every time though that was on a British stove. Not so likely on an Optimus.
     
  12. snwcmpr

    snwcmpr Subscriber

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    Soft solder repair would be the fix for removing and replacing the pump tube. There are great instructions here.
    Hard use of the NRV tool. (?)
    But, all that after all other avenues.

    I use fine steel wool to polish the brass in NRVs.
    I have a bunch of new NRVs that need work, a lot, before using. I posted that somewhere.
    Others have worded what I meant earlier much better than I did.

    Burrs and crud at the sealing areas. Easy to cleanup.

    Ken
     
  13. Ray123

    Ray123 Subscriber

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    I had a cracked pump tube on a Petromax 100. It does happen occasionally although I'm not sure how.

    Empty the fuel, pump it up and pour water into the pump tube and as Ken says you should be able to locate the leak source. Bubbles will come from the center hole of the valve, around the sealing washer or a crack in the tube.
     
  14. hikerduane

    hikerduane Subscriber

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    One cracked pump tube here too on a British 96.
    Duane
     
  15. The Warrior

    The Warrior United States Subscriber

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    I noticed many are HDPE. I got the LPDE from a video I watched, where a guy rebuilt a 111, and used LPDE for the rebuild, making his own from food contained lids. Not saying that's a good thing, but that's where I got that at.
     
  16. Simes

    Simes Subscriber

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    @The Warrior, takeaway food containers don't enjoy being kept warm in an oven for any length of time, and it's quite brittle to begin with. :(

    The lids will fuse with the container quite happily not much above 'low' in an oven.
     
  17. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    ‘Been there, done that’ Simes?!!
     
  18. Simes

    Simes Subscriber

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    :( :( and I've done it more than once as well.....

    ..it'll be ok while I get everything else ready,,,then it's knife or scissor attack to get at your food...
     
  19. The Warrior

    The Warrior United States Subscriber

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    So, does everyone agree that lead is the best bet? I just purchased a 111B that should be here Monday, and snwcmpr was the one that informed me about replacing the pip on the NRV. I didn't even know what a NRV was. New to this. I now know that a NRV and check valve are one in the same. Where's a good place to get a replacement kit? If I order here, from England, how will it take to get here? I'm in Illinois.
     
  20. BradB

    BradB United States Subscriber

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    Just put in my 3rd NRV and it seems to be working. I noticed number 3 seemed to work much smoother than the others before I installed it. I will smooth up the others before installing, lesson learned. I am not ready to declare victory as experience has taught me that one successful burn does not mean it will work the next time. These one pinters are testing my limited skills. Thanks all for the input, I will report more as needed. Brad