Somewhere, at the bottom of all of the plastic BS... there is still a screw.
I lived in northern Colorado for a few years. Limiter caps seem to fall off there.
With the carb on the bench, you can figure out how to fix things. Sometimes it takes a red hot utility knife blade - will not hurt the metal screw at all.
As for making fuel adjustments, it is the responsible thing to do - because at high altitudes they run RICH, and you are doing the right thing by adjusting the carb.
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