As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS IN MAINTENANCE FOR CARBURETOR HEAT PROBLEM AND MECHANIC NOTED THAT AD 86-24-07 WAS NOT C/W. AIRCRAFT HAS BEEN MODIFIED WITH INSTALLATION OF 180 HP LYCOMING ENGINE IAW STC SA421CE AND SA749CE. AD 86-24-07 DOES NOT LIST 170B AS APPLICABLE. SE 79-6 DOES NOT CALL OUT SPECIFIC MODELS, BUT DOES REQUIRE DRILLED BOLTS ON ALL BALL BEARING TYPE CONTROLS.