Optimus 350/350cp goes out

Discussion in 'Fettling Forum' started by Leo77, Feb 22, 2024.

  1. Leo77 Switzerland

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    Hi!
    I'm new here and have an Optimus 350/350cp, which I'm trying to get going. I've replaced the pump leather and can pump it up (releasing the fuel gap screw gives a 'pffff'). After priming it with ethanol, and turning the knob, it lights okay, burns for a bit, but then just gets dimmer and goes out. Could I be using the wrong fuel? I'm using a fuel bought in Switzerland made by Pelam labelled "Paraffin" in English. I guessed this is Kerosene, but perhaps not. It also says "Usable as cleaning agent".

    Does anyone of this is kerosene, and if not where I can buy kerosene in Switzerland & what it's called?

    If the fuel is not the problem, can anyone suggest what I might need to tinker with to get it going properly? Before it goes out, it's burning bright and clean.

    Cheers,

    Leo
     
  2. Matti Kucer

    Matti Kucer Sweden Subscriber

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    If the lantern has been cleaned properly it may be a fuel issue. It’s common that people uses fuel intended for wick lanterns and after changing fuel all is well.
    Do check what fuel You have in your lantern.

    Regards Matti
     
  3. Leo77 Switzerland

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    Hi Matti,

    Thanks for your reply.

    I haven't done a full service. Perhaps that's a good plan. Do you know a video or clear instructions for how to do this?

    Cheers, Leo
     
  4. Matti Kucer

    Matti Kucer Sweden Subscriber

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    Hi!

    Go to the post below and open the guide there. It will help you!
    Petromax 826 clean up/restoration guidance needed
     
  5. Nils Stephenson

    Nils Stephenson Founder Member

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    You say it holds pressure, but how long does it hold pressure? The symptoms you mention could indicate loss of pressure. A service and replacing seals and washers might help.
     
  6. Fireexit1 United Kingdom

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    At the risk of repeating the wise advice already given - I always put new seals in - if for nothing else - peace of mind that I will not have to deal with loss of pressure or fuel. Apart from safety concerns it removes it from the list of problems.
    I think in Germany Paraffin is called "Petroleum". (Pétrole in French) Generally is is similar to oil fired heating oil but a little more refined. Or if you can get it Aviation turbine fuel. But generally anything marketed for hurricane lamps ( Sturmlanterne, Lanterne tempête ) does not work well.
    These are very well made lanterns and worth fixing/using - so keep going !
     
  7. MYN

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    Are you using this?:-
    pelam-lampenoel_49219_1.jpg
    If I'm not wrong, this should be useable as fuel for kerosene pressure lamps such as your Optimus, Petromax as well as wick lamps.
    It is highly refined, with mostly
    hydrocarbons, C₁₀-C₁₃, n-alkanes, isoalkanes, cyc-
    lics, < 2% aromatics. It has a narrower boiling temperature range, approximately between 186-214°C, which, is still within the wider range of 1-K kerosene. We normally prefer 1k-kerosene for such lanterns if it is available.
     
  8. Leo77 Switzerland

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    Hi everyone,

    Thank you all so much for the tips!

    @Matti Kucer that guide was really useful, and helped me do a service with parts from BaseCamp uk.

    @Nils I replaced all the seals, the NRV (it was cracked), graphite packing in the control-knob, needle, and the bottom valve. I just fired it up tonight and it goes! Now the only issue is the mantle has a dark patch (hoping that will go away) and it pulses quite noticeably (I've read that brass mesh around the needle rod might help so I might try that, or stretching the spring in the lowest valve??)

    @Fireexit1 great tips on replacing the washers and finding fuel – thanks! I have two 350 / 350CPs and one 200 and am slowly learning the ropes with them. I hope to get them all up and running.

    @MYN – that's exactly what i'm using right now – it took me a while to find, and i wasted some time with other products, but this seems to go well. The next challenge will be to get it in bulk! How do you know so much about fuel?

    Thanks again everyone for your tips. Really appreciated.

    IMG_5685.jpeg
     
  9. Fireexit1 United Kingdom

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    Looking great !
    You may find that mazout works well in your lanterns. I know little or nothing about Swiss fuels. Here in the UK it is known as Fuel Oil and it is possible to buy "cleaner" versions of it.
    Another source if fuel is "Avtur" - so aviation jet turbine fuel. Swissair use a version 100% made from bio fuel. It would be interesting to see if that works in a Kerosene lantern (Thinking of the future)
     
  10. MYN

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    @Leo77
    You have a well-lit Optimus there.
    Congratulations.
    Anyway, I don't really know that much about fuels,.. just a tiny bit more than the usual working knowledge. That's probably a 'byproduct' of my own interest about fire, fuels, flammable liquids and such since I was a kid.
    I'm not sure if you could conveniently get bulk Pelam Paraffin in Switzerland. If I've not mistaken, they also supply them in 10-litre containers. It doesn't seem to be that cheap either.
     
  11. Sellig33

    Sellig33 France Subscriber

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    @Leo77
    My 630 run with this :
    20240406_195101.jpg
    And she run well
    20240406_195616.jpg
     
  12. Johan Källström

    Johan Källström Sweden Subscriber

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    "I believe the issue may be related to the valve at the end of the tube inside the tank. The cleaning needle rod has a pointed tip that presses against a rubber cone inside the valve. In my experience, this design is not ideal. Over time, the pointed tip creates marks in the rubber cone, causing it to move slightly upwards, which partially seals or restricts the fuel flow. I removed the valve and took out the rubber cone. Now, my lantern works perfectly. Of course, this modification means that the shut-off function with the control knob won't work as before, but I always release the pressure using the air screw when I turn off the lantern anyway, so proceed at your own risk.

    This tip might be the solution to your problem. Does the flame pulse slightly before it goes out completely?"
     
  13. Martin K.

    Martin K. Subscriber

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