MSR Yellow pinned pump

Discussion in 'Fettling Forum' started by 8R Pete, Mar 14, 2020.

  1. 8R Pete

    8R Pete United States Subscriber

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    I have maybe 6 MSR yellow pinned pumps-what would cause the pump to fill with fuel while pumping?white Teflon disc, spring, and small brass piece is all there. I tried to use the 1 pump and fuel came out the small hole on top of the plunger. Any ideas?
     
  2. snwcmpr

    snwcmpr SotM Winner Subscriber

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  3. 8R Pete

    8R Pete United States Subscriber

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    I hope so. Please Doc!
     
  4. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    @8R Pete
    The seal is made between the teflon disc and an O-ring, visible when the fuel tube and pins, spring and disc are removed.

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    The O-ring will be damaged, perhaps hardened and cracked. Less likely is that the teflon disc will be damaged but that should be checked too.

    John
     
  5. 8R Pete

    8R Pete United States Subscriber

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    Thank You Presscall-I will check that O-ring today!
     
  6. lanevitt

    lanevitt Subscriber

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    I have my teflon disc AWOL on my yellow pump.. any idea as to its thickness ? I see small sheets up for sale on Ebay at 0.5 and 1mm thickness.
    I aim to have a go at cutting one out to replace the missing disc.. Is it O ring first in then the teflon disc, follwed by the spring etc ?
     
  7. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    Hi Andrew. Yes, O-ring sits in the pump, then disc, then spring, then the little brass ‘olive’ component in the end of the fuel pickup tube, held in place by the steel pins.

    I punched an alternative to teflon out of 0.5mm brass sheet. It makes a good seal and has held up fine.

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    John
     
  8. lanevitt

    lanevitt Subscriber

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    Hi John

    Thanks for the info'.. I was toying with the idea of alternative materials, but brass escaped the list.. I have purchased a small sheet of 0.5mm teflon from Ebay.. only £1.25

    andrew
     
  9. Doc Mark

    Doc Mark SotM Winner Subscriber

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    Greetings, All.

    Sorry to have been AWOL. Work has been demanding, as usual, and I have not had time to visit here, nor anyplace else, lately. HUZZAH to John @presscall , for stepping up to the plate, and slamming one over the right field fence!! Well done, my friend! All your suggestions are spot on the money, as usual!! Thanks, again, and God Bless!

    Every Good Wish,
    Doc
     
  10. 8R Pete

    8R Pete United States Subscriber

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    Thank You for the replies. I replaced the O-ring- I had to use a safety pin as it is in there out of my fingers reach. Now the question-The little twist pins-what can I be used to replace 1 that fell in a crack in my driveway? can I cut down a brad and use that?
     
  11. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

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    Since you’ve one of the originals left you’ll notice the coarse threads on it, there to ensure it stays put. By ‘brad’ you mean an un-threaded tack, or pin I suppose. I suggest a cut-down screw to replicate the original as much as possible.

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    The pins don’t just hold the fuel pickup tube in place - there are a couple of holes in the tube diametrically opposite that the pins pass through - but a chamfer on that little brass ‘olive’ component butts up against the tips of the pins and that in turn prevents the NRV spring from unseating.

    You get my point? The pins have got to be secure and not be pushed out by the spring tension on their tip, applied by the brass component.
     
  12. 8R Pete

    8R Pete United States Subscriber

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    I know what you are saying-now got to find a screw small enough.
     
  13. snwcmpr

    snwcmpr SotM Winner Subscriber

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    May have to make something with a dremel, then twist it.