Before we get into the nuts and bolts of the Honda 21-inch Variable Speed 4-in-1 Gas Walk Behind Self Propelled Lawn Mower we should point out that the model numbers HRX217VKA and HRX217K5VKA are used interchangeably by Honda to refer to this lawn mower and there do not appear to be any differences between the two. That said the best adjective to describe the HRX217VKA is powerful.
Other items and supplies include a plastic drip tray motor oil and a container for waste oil. Often a large piece of cardboard is useful as well an old rag or cloth. Also know that this guide deals with push or self-propelled mowers not riding mowers. While some advice here applies they are another animal altogether.
Next you will change the oil. To lower oil viscosity and get it moving freely run the engine for a few minutes. Now shut the engine off and roll the mower onto a piece of cardboard or drop cloth. Close the fuel line (if your mower has one) and unhook the spark plug as before. Find the oil filler tube and remove its cap. Often the cap also functions as a dipstick.