Originally posted by Corse-R
Kevin:
It's easy to solve, remove idle speed screw, loosen the rubber boot and the barrel should go. Remove the low-end needle by unscrewing and assemble another time. Don't know why but problems disappear when you did this (now that is disassembled the carb, take a look to ensure that everything is ok).
As a routine, each engine I buy I'll disassemble completely and ensure that nothing weird is in places that can make a big ouch! when engine is started. 
Thanks Corse-R. I did disassemble it. Someone also told me maybe to rub the needle a bit with scotchbrite, just to ensure no sticking. I ended up dropping a carb from an MT-12 into it instead. Seems fine now.
