As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED POWER LOSS IN CRUISE FLIGHT AND COULD NOT MAINTAIN ALTITUDE. PRECAUTIONARY LANDING WAS MADE ON HIGHWAY, MINOR DAMAGE TO AIRCRAFT; NO INJURIES TO PILOT. INVESTIGATION REVEALED A WAS OF STEEL WOOL IN THE VENTURI OF THE CARBURETOR. STEEL WOOL HAD BEEN PLACED IN THE HEAT MUFFS TO INCREASE HEAT TRANSFER. THE STEEL WOOL EXITED THE SMALL HOLE IN THE MUFF, WENT THROUGH THE SCAT HOSE AND INTO THE CARBURETOR CAUSING THE POWER LOSS. (SO05200505084) (K)