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High Elevation Motorcraft 2100

Discussion in 'Early CJ5 and CJ6 Tech' started by wheelie, May 15, 2021.

  1. wheelie

    wheelie beeg dummy 2024 Sponsor 2023 Sponsor

    Looking for first hand experience here. I've read and talked to several folks about general adjustments in jet size for running at high elevations. Looking for jet size recommendation for 10,000 ft. I'm at at 700- ft now so it's quite a rise.

    The 2100 I'm running on my OF 231 was built by a guy that was recommended by members here. Unfortunately, he (the carb builder) seems to have disappeared and I cannot contact him. He asked about my elevation when he put my carb together so I assume he jetted it correctly for my location and it DOES seem to run great here. But, I have no idea what jet size he used.
     
  2. SFaulken

    SFaulken Active Member

    You will need to go to smaller size jets as you get up in elevation. Less air at higher elevation, so it's going to be stupid rich at 10,000 Feet ASL. The general rule of thumb is to go down one jet size per 2000 feet of elevation.
     
  3. colojeepguy

    colojeepguy Colorado Springs

    It takes about 5 minutes to pull the top off one of those, then you'd know for sure what's in there,.
     
  4. SFaulken

    SFaulken Active Member

    Technically, you can change the jets on a 2100/4100 while it's running, if you're brave.
     
  5. colojeepguy

    colojeepguy Colorado Springs

    I once tried running the engine with the top off the carb...of course it popped back through the carb and we had a merry little blaze going in the float bowl :shock: Lesson learned!
     
    Twin2 and SFaulken like this.
  6. SFaulken

    SFaulken Active Member

    Oh, it isn't a good idea, but it can be done. =P
     
    colojeepguy likes this.
  7. wheelie

    wheelie beeg dummy 2024 Sponsor 2023 Sponsor

    Yea. Just didn't get there yet. Planning stage and soon to get to work on it. And, uhh, I'll opt for safer option of changing jets with the engine off thank you very much. It does sound like fun though.
     
    Rich M., Twin2 and colojeepguy like this.