Strange burning on Coleman 424

Discussion in 'Fettling Forum' started by SulphurTX, Jun 1, 2026 at 9:28 AM.

  1. SulphurTX Netherlands

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    May 26, 2025
    Messages:
    10
    Location:
    The Netherlands
    Hello everybody,

    I bought a 1996 Coleman 424 stove last year and replaced the generator shortly after purchasing it. The stove worked perfectly for a few months, but then it suddenly started producing yellow flames and became much harder to get burning properly.

    I tried to fix the issue myself, but I'm not very technical and didn't have all the proper tools. While replacing the graphite packing, I may have damaged the generator cleaning needle and the fuel control knob assembly. See a video of my stove while burning:

    To rule that out, I ordered and installed a brand-new generator and valve assembly, but unfortunately the stove still burns strangely.

    The symptoms are:

    • Yellow flames at certain fuel knob positions
    • Black soot on pots and pans
    • The flame sometimes increases in intensity by itself without me adjusting the control knob
    • It is difficult to achieve a stable blue flame. I can usually get it burning correctly eventually, but only after building up a lot of pressure in the tank.
    • The stove is much harder to get running smoothly compared to when I first bought it
    Things I have already tried:

    • Using fresh Aspen 4 fuel
    • Replacing the generator with a new one
    • Replacing the valve assembly with a new one
    • Cleaning the manifold (no spider webs or obstructions found)
    • Cleaning the burners
    Does anyone have an idea what could be causing this? Could there be an issue with the fuel/air tube inside the tank, tank pressure, or something else that I'm overlooking?

    Any advice would be greatly appreciated.