I checked out my neighbours lawn mower that was basically inoperable. It's on a recreation property and I noticed she was falling behind on her upkeep. It's a Briggs Quantum 6 HP manufactured in 2005. Here is the air filter. I also changed the oil and I'm not sure if it was ever changed before. There was also a missing bolt on the handle which pretty much made it impossible to push. No wonder she was getting behind. It's all tip top now. Enjoy.