funky Choke on a 125 SM

i started trying to use the choke now that the temps have dropped 20-30 degrees.
first 'notch' sounds absolutely no different from the Off position, and i have to keep the throttle slightly for 5 minutes to let it warm up.
the 2nd 'notch' causes the engine to rev up steadily for just under 2 seconds, followed by the engine stall.
after this, the engine doesn't start unless i remove the seat and cup the air intake, while hitting the starter.
is there any generic cause for this? what do i need to adjust?
first 'notch' sounds absolutely no different from the Off position, and i have to keep the throttle slightly for 5 minutes to let it warm up.
the 2nd 'notch' causes the engine to rev up steadily for just under 2 seconds, followed by the engine stall.
after this, the engine doesn't start unless i remove the seat and cup the air intake, while hitting the starter.
is there any generic cause for this? what do i need to adjust?