Choke ON and revving at 9K is way, way too high!!!
An engine will only rev to RPM supported by incoming air-volume. Revving to 9k at idle with throttle-closed means engine is sucking in TWICE as much air as normal. Where's it getting all this extra air???
Bob's onto something, maybe there's vacuum-port or line somewhere that's not plugged in perhaps and is letting carb suck in extra air. This will also cause starting and idling issues since extra air will cause lean mixtures (without choke). Just coincidental that it works better with choke ON because that supplies extra fuel after-the-fact to match extra air. Root cause issue is there's extra air getting into carbs somehow.
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