Only after warm up,...Issues

Hmmm? Very strange. The 1695 carb has constant vacuum at the vacuum advance port. With that said, it's always advanced. I unhooked and plugged the port on the carb (I haven't taken it out for a ride yet), but believe it or not it seems to be running better at idle then it was when the vacuum advance was hooked up. Anyone know why it would have constant vacuum at that port? That can't be a good thing!!
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