NGK spark plug. The spark plug ignites the fuel and air mixture in the cylinder to power the engine. If the spark plug is burnt, fouled or damaged the engine may not start or may run rough.
Lawn mower pinion gear. 12 tooth. Engages the drive wheel, also center cam allows the mower to be pulled backwards
Lawn mower ratchet return spring. Helps allow drive wheel to move backwards when forward drive is not engaged
Lawn mower ratchet key. The ratchet key engages the drive shaft to the drive gear to turn the wheel. A small spring keeps tention on the key. If the key is not engaging the gear it may be worn and will need to be replaced. It is a good idea to also check the spring and replace it if necessary.
Lawn mower air cleaner cover. If this cover is cracked, or if one of its holding tabs is broken, replace it.