what's the right oil for a honda hrn216vka lawn mower and how often do i change it?

Use SAE 10W-30 oil with an API service category of SJ or later. Change it per the maintenance schedule. Oil is a major factor for performance and engine life.

For other temperatures: use SAE 5W-30 below 40°F (4°C), or SAE 30 above 50°F (10°C). Always check the level with the dipstick on a level surface before each use.

Do not overfill. White smoke from the muffler signals overfilling.