I also noticed my carb boots popped of #1 and #2.
Check to see if the boots are still pliable when they are at or near room temperature. If they are hard as plastic and not rubbery anymore, they have probably shrunk a little. A heat gun or blow dryer may help get them back on with a lot of pulling, tugging, cussing, and bleeding. Get the bottom started first where you can't see it. Some of us have created special screw drivers or stout wire bent to a hook on the end to assist in this task. Don't tear the rubber.
If not, you are looking at getting new ones which will slip on easily.