If you find a setup similar to yours but at lower elevation this may help
https://www.jetsrus.com/FAQs/FAQ_rejet_elevation_and_temperature.htm
Maybe Awk can make that link a pinned topic
What is the black plastic screw (idle screw?) supposed to be set at?
that's open like 1/3 throttle, and is why it's idling so high
take the cable off and back the idle screw out the whole way to see if it slides down all the way
has to be one of those 2 holding it up that high, it should be down so far you doubt it's flowing any air, but it will
edit: is this one of those that the slide can be put in backwards ?
I snapped some pics of the slide on the carb, is this position why it’s idling so high? I’m new to this carb and I can’t get the slide to come down any further.