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CEJN fitting strip-down

Discussion in 'Fettlers Master Class' started by presscall, Apr 18, 2012.

  1. SNOWGOOSE

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    Last edited by a moderator: Jul 1, 2015
  2. presscall

    presscall United Kingdom Subscriber

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    Ah, Snowgoose got his reply in first. Makes sense to go for the Optimus spare, though as I noted in my original post I happened to have a Primus Omnifuel O-ring (part number 731905) - £2 from CCS Base Camp - that was also a fit.

    John
     
  3. vargen77 Sweden

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    What is the size on the o-rings in mm
     
  4. presscall

    presscall United Kingdom Subscriber

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    @vargen77
    I had reason to return to this thread to consult it for repair of a fitting and noticed your post. I recommend the 'Alert' feature on the site to make sure a question doesn't get overlooked as yours was.

    I don't know the size of the O-ring, sorry. Approximately it's 6mm outer diameter and 3mm inner but there's no precision in my measurement. Primus Omnifuel O-ring (part number 731905) will work.
     
  5. vargen77 Sweden

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    Ok thanks will check that out
     
  6. NP4-8-4

    NP4-8-4 United States Subscriber

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    O-ring size for CEJN from USA source:

    McMaster-Carr
    600 N County Line Rd
    Elmhurst, IL 60126-2081
    Chi.sales@mcmaster.com

    I ordered the following:

    Mil-Spec Fluorosilicone O-Ring, mil-R-25988/1-006

    Many thanks to Presscall for his [usual] detailed photo-essay on how to dismantle an old style Optimus Nova pump with a CEJN fitting. I had used this stove on a backpacking trip to Rocky Mountain National Park this past summer. Towards the end of the trip I began to experience difficulty with the CEJN valve sticking "open" so that fuel would leak out of the filling. Searching the site for repair ideas I came across this thread. Presscall's suggested use of a Primus O-Ring and the accompanying photo made me think that the Primus O-Ring, in comparison to the Nova's CEJN O-Ring, looked similar in size to the O-Rings I purchased from McMaster-Carr to service my Coleman 222 lanterns. I finally had some time to fettle the fitting this evening. Dismantling the CEJN fitting and comparing its O-Rings with the McMaster-Carr O-Ring revealed a nearly perfect fit. Although the Nova's rings were intact and still pliable, I replace them nevertheless. Just fired the stove and it functions as it should. Perhaps it was the MSR mineral oil I slathered on the rings that restored operations to normal. In any event the stove runs fine with the O-Ring noted above.

    McMaster-Carr's prices seemed reasonable and they shipped very quickly.
     
  7. presscall

    presscall United Kingdom Subscriber

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    @NP4-8-4
    I'm pleased your repair was successful and glad to have assisted with the write-up.

    That's a really helpful reference for the O-ring source.