As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ENGINE HAD JUST OVERHAULED AND FOUND TO BE RUNNING ROUGH IN THE LOW RPM RANGE. DIFFICULTY FOUND IN ADJUSTING IDLE MIXTURE. AFTER REVIEWING FAA AD 98-01-06 DECISION TO REPLACE CARBURETOR WAS MADE. CARBURETOR REMOVED HAD THE ONE PIECE VENTURI.