SH&S Underburn

Discussion in 'Fettling Forum' started by ally, Mar 20, 2020.

  1. ally

    ally Subscriber

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    Hi all

    I have recently received my first SH&S 2 pinter which I have been unable to get firing correctly

    Initially I would get a very rich mix with mostly yellow flame, at very low pressure I would get a somewhat blue flame but totally unusable

    whilst tapping the burner head the flame went out so suspected just a fouled burner, I did a tentative heat and quench after a turn in the ultrasonic bath and did get a modest amount of carbon debris out

    However, the same burn pattern, I replaced the jet and whilst somewhat better it was still a very rich burn with lots of yellow

    I tried swapping the flame ring and silent cap with slightly larger dimensions from some in 'stock' which improved slightly again but would almost immediately go to an underburn so have just tried a new in the box ebay burner I purchased ages ago and it lights and then within a second or two goes to an underburn

    I'm lost, any advice...

    :)
     
  2. Lennart F

    Lennart F Sweden Subscriber

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    When it happens with different burners and a new jet does very litlle improvement - I would suspect the fuel for partially clogging the jet.
    Some sorts of "lamp oil", especially those with large amounts of vegetable oil tend to do that - often labeled "bio-" or "environment friendly".
    Could be some contamination in otherwise good kerosene/paraffin too.
     
  3. hikerduane

    hikerduane Subscriber

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    My cobra burner Optimus stoves don't like dyed kero, clear is all they will burn.
    Duane
     
  4. Simes

    Simes R.I.P.

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    @ally the only thing I can suggest is cleanliness. Both fuel supoly and all inner and outer caps. Any flakyness on either of the caps can prompt it.
     
  5. ally

    ally Subscriber

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    thanks guys, it had me baffled

    I'll give the tank a purge and clean, will let you know

    :)