Yer idle jet is clogged, and / or the choke isn't choking when cold.
Manual choke?

Clean out the idle jet, and try again. It is a tiny hole in the side of
the barrel of the carb, close to where the throttle butterfly edge
rests when closed, or in the idle position. Often, poking at it with a
toothpick is all it needs, or blowing out with air. I had a carb seal
itself off at the main jet intake, with a blister of gasoline varnish.
Popped it, and all was well. Had to take it apart to find it

The carb needs maintenance by a guy that knows carbs, a dying trade
now, with fuel injection being so much better.

Terry K