Performed level 2 furnace cleaning and replaced the inducer motor. I had to completely disassemble the furnace venting and gas pipe to get the motor out. After installing the new motor and put everything back together, I was able to perform the cleaning. Burners are clean. Heat exchanger and ignition assembly are showing signs of wear. Gas and exhaust levels are normal. No CO detected in the air. Heat rise was 50 degrees. Due to age and condition, annual maintenance is recommended. Furnace is operating normally at this time.