[midniteblues]

You might wanna check the intake bolts too see if they are loose and the intake gaskets for a vacuum leak.
it could be sucking oil when the carb is fully choked then then when it opens some not sucking so much oil. Also from the engine warming up everything is expanding and could seal up the internal leak.
your idle might change if it's sucking extra air also this could be why your rpms are not dropping.
Then there is always the suspect choke acting weird.

But the valve seals can have the same symptoms but from what i have seen is usually it will always puff warm or cold from bad valve seals.