Good advice all over the place here but I've had two of these OS 46 FXs and I've seen two more at my club ALL have the same problem. Part of the difficulty in getting the midrange right is the remote needle on this engine and it is very hard to get it to idle without loading up. Follow all the good advice here and run your 46 until it wears out then get a Thunder Tiger, older OS, Irvine or Tower Engine.

Good luck.

Ignacio