As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CARBURETOR HEAT VALVE BROKEN AND PARTIALLY JAMMED. SHAFT ROTATING NORMALLY. NO HEAT GETTING TO CARBURETOR BRACKET. FILTER NOT REPLACED SINCE 1991, OVER 400 HOURS. SUBMITTER SUGGESTS NEOPRENE GASKET IS A POOR DESIGN FOR GRUMMAN AA-1C AIRBOX, VERY LITTLE OF THE GASKET IS SANDWICHED AT THE LOWER LIP.