Inspect the floats really well , floats can crack and actually fill up with gas and then they don't float and it will act like that because its getting too much fuel at the main jet but the idle circuit isn't really affected . If the floats are fine , you need to set the height correctly and to do that you need to do some reading and get a tool thats relativley inexpensive but will make the job easy ( ish ) . Needles and seats do wear out , typically the seat will look Oval instead of round and thats a tell tale sign of it needing replacement . I would check it all again , put it together in the stock form just as the manual says and start from there .