You need not be a riding lawn mower expert to understand that engine sputtering is not a good thing. Luckily, it’s not the end of the world (not yet, anyway), and you won’t need to worry about running out to the store - or Amazon, more likely - to order a new mower for immediate delivery. That being said, if your engine is sputtering, then you should fix it as soon as possible, as leaving it will only exacerbate the issue. To solve it, there are several things you can try.
Check for water in the gas tank, possibly from wet weather or moisture. Tip the gas tank over and empty it into a container.
Change the oil by turning the oil case over so it’s under the carburetor. Drain the oil from the mower and replace it with the specified oil in your owner’s manual.
Replace the filter if it’s dirty, as this hinders ventilation and can lead to a build-up of dirt and debris. You can also wash the foam filter with soap and water and allow it to dry.
Check for caked on and dried grass as this is also a cause of sputtering due to blockage. Use a scraping tool to remove it, but make sure you remove the spark plug to stop the mower from turning on while you’re doing it.