Optimus No. 00 Pump problem

Discussion in 'Fettling Forum' started by Haydino, Mar 31, 2020.

  1. Haydino United Kingdom

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    Hi Everyone,

    It’s my first post on the forum and recently, I’ve been working on a Optimus No. 00 and fettling it ready for use.

    I took out the pump to take a look if the cup was still in good condition... I was greeted by not a leather cup, but instead a rubber o-ring that was brittle and what appears to be a botched together pump.

    I’m new to fettling these stoves however, from what i have seen i’m certain the pump should not be put together like this and the the thread is missing on the end of the pump rod. Does anyone know how to go about acquiring a new rod and end assembly?
     

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  2. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi @Haydino . Welcome to CCS.

    It looks from your photo that you have parts of an “O-ring” pump as fitted to last Optimus No.00 stoves that Optimus produced:

    Optimus No.00L "Camper". Made in Sweden, Early 1990's. Un-used.

    If you scan through the images you will see photos of the pump assembly.

    The piston arrangement is basically a sandwich, comprising an O-ring between two washers, held onto the pump shaft with a spring washer fitting (which you appear to show in your photo.

    Not my favourite type of pump, but I guess it was cheaper to produce!

    Base Camp should be able to sell you a replacement leather based piston assembly and pump shaft

    Best Regards,
    Kerophile.
     
  3. Haydino United Kingdom

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    Thanks for the warm welcome!

    Ah! I just assumed it was a botch! Would any generic O-ring be okay as a replacement? I'd like to keep it all original ideally, As it came in the original tin.
     
  4. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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    Hi @Haydino A quick look suggests you have all the original parts there, although the O-ring is fragmented.
    I would suggest that a suitably sized O-ring, preferably fuel resistant, like Viton or high grade Nitrile should do the business once you have everything cleaned up and polished. The O-ring should be lubricated with a small amount of silicone grease.
    In principle the O-ring should not come in contact with the paraffin fuel in normal use. However if the NRV leaks and allows fuel to enter the pump cylinder, you don’t want the O-ring to dissolve!
    Post some photos once you have your stove working well.

    Best Regards,
    Kerophile
     
  5. Haydino United Kingdom

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    I've ordered a new pack of O-Rings, should be here in a couple of days! Thanks for the help!
     
  6. Ed Winskill

    Ed Winskill United States Subscriber

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    Welcome to CCS.
     
  7. IvanN

    IvanN United States Subscriber

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    Welcome! The 00 is an excellent stove. You should be up and cooking soon.
    Ivan
     
  8. Haydino United Kingdom

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    Thanks! I'm looking forward to using it on my bushcraft outings!
     
  9. kerophile

    kerophile United Kingdom SotM Winner Subscriber

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  10. Haydino United Kingdom

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    Quick update on the stove!

    I ordered a new seal kit from Juliands and replaced all the seals on the stove. I've also replaced the o-ring seal on the pump and as Kerophile suggested, it has been finely coated with a silicon grease.

    The stove is now holding pressure and the pump has improved dramatically in performance.

    I'm just waiting on some new lead washers to arrive from fettlebox to replace the rather mashed up one in the burner.