ORIGINAL: Ed Cregger
Drop down to a 9x4 or 9x5 prop. A 9x7 is causing you to tune the high speed needle way to rich. The midrange metering is fixed, but associated with the high speed needle. By tuning way rich to compensate for too much prop, the midrange becomes way too rich for good running.
Yet another one for dropping the prop size down. I run 9x7s on my OS .32 FSR and it's really happy with that size.