As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED THAT ON CLIMBOUT, THE RT PROP BECAME UNCONTROLLABLE AND WOULD OVERSPEED. THE PILOT ELECTED TO RETURN TO THE DEPARTURE AIRPORT. UPON MX INSPECTION, THE RT PROP AND PROP GOVERNOR WERE REPLACED IAW MM CHAPTER 61. THE PROP OPS AND LEAK CHECKED GOOD.