Diff’rent Strokes - O-ring pump/leather pump cup

Discussion in 'Fettling Forum' started by presscall, Feb 22, 2020.

  1. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    Anyone who followed the saga of my efforts to transform a Russian Prim Compact from a stove with no simmering capability into a functional ‘user’ could be forgiven for thinking I’ve become obsessed by it!

    The existing pump wasn’t a model of efficiency. An O-ring serving instead of a leather pump cup rarely is.

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    Made worse on this one by an over-sized bearing clearance in the pump cap. That’s not wear, it’s the original specification.

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    Coupled with the short stroke, the aluminium flanges enclosing the O-ring could be felt to intermittently scrape along the pump tube wall in action. Eased by lubricant, it nevertheless gave the pump action a certain harshness.

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    I’ve replaced it with this, made up from ‘brassie’ stove parts.

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    Crucially, the leather pump cup is mounted in the way best described here by @kerophile :
    Essential too, to get rid of that slack pump cap, replaced by a close-fitting end cap.

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    Presently a tight push-fit on the part of the pump tube projecting from the fuel tank, I’ll be installing a Coleman-pattern spring clip retainer.

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    Last edited: Feb 22, 2020
  2. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    Done.

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  3. The Warrior

    The Warrior United States Subscriber

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    In the 'Nois man.
    Heck yeah man, nice work.

    Need to get my 111B changed to leather.