Sounds like you have it well out of whack. Reset the high speed needle valve for max RPM then richen it (counter clock wise a 1/4 turn). Then idle it down, use a very small screw driver - 3/32 of an inch -- and insert it on the other side of the carb from the high speed needle valve (do this adjustment with the engine stopped for safety purposes). This is the low speed adjustment screw (the low speed setting determines the idle and transition to high RPMs). It sounds as though this is all the way in or near all the way in. Unscrew it at an 1/8 of a turn at a time, gradually richen the idle setting. Run and test. Keep at it until you get a good idle and a good transition. You may have to reset the high speed needle after just a 1/4 turn or so of the low speed adjustment. You are looking for the right balance. Take your time and work at it. It will come around for you.

Cheers,

Chip