Lawn mower maintenance checklist
Updated August 2026
A mower's season is short and specific: fresh oil, a sharpened blade, and a clean air filter each spring, a new spark plug about once a year, and stabilized or drained fuel before winter storage. A dull blade tears grass rather than slicing it, leaving frayed brown tips that invite disease, and stale fuel is the classic reason an engine will not fire in spring. Keep up and a mower comfortably reaches its 8 to 10 year life.
| Task | Interval | Effort |
|---|---|---|
| Scrape clippings off the underside of the deck | As needed | 10 min · DIY |
| Task | Interval | Effort |
|---|---|---|
| Change the oil | Each season or 25–50 hrs | $5–15 · DIY |
| Sharpen or replace the blade | 2x per season | $10–25 · DIY |
| Replace the air filter | Each season | $5–15 · DIY |
| Replace the spark plug | Yearly or 100 hrs | $3–8 · DIY |
| Task | Interval | Effort |
|---|---|---|
| Add stabilizer or run the tank dry | Before winter | 15 min · DIY |
What neglect costs
Neglect shows up two ways. A dull blade bruises and shreds the grass, browning the lawn and opening it to fungus, and it costs nothing to prevent with a twice-a-season sharpening. The mechanical bill comes from fuel and oil: ethanol gas left over winter gums up the carburetor, a cleaning or rebuild a shop charges $75–150 for, and running low or old oil scores the cylinder and kills the engine outright. Either way a mower that should last 8 to 10 years dies in three or four.
Leave these to a pro
Nearly all of this is driveway-level work, but a few repairs are worth a small-engine shop. A carburetor that will not clean up, a blade that needs rebalancing on a machine, and any valve, governor, or pull-cord recoil work run faster and cleaner in trained hands. A full shop tune-up, covering oil, blade, filter, plug, and a carburetor clean, typically runs $60–120, which can be worth it the year you would rather not touch the fuel system yourself.
This whole checklist ships as reminders in OnOtto: every task above, on the right schedule for your home, snooze-proof.
Load this checklist as remindersFrequently asked questions
How often should I change the oil in my mower?
Once a season for the average homeowner, or every 25 to 50 running hours if you cut a large lot. A brand-new engine also wants its first oil change after the initial 5 hours to flush out break-in metal. Most walk-behind mowers hold only 15 to 20 ounces, so it is a five-minute, ten-dollar job. The oil-change guide covers the right weight and the tip-and-drain trick for mowers without a drain plug.
How do I know when the mower blade needs sharpening?
Look at the grass, not the blade. If the tips are ragged and turn tan or white a day after cutting, the blade is tearing instead of slicing, and the lawn is more vulnerable to disease. Most people sharpen twice a season, or roughly every 20 to 25 hours, and replace the blade when the cutting edge is nicked deep or worn thin. A fresh blade runs $10 to $25. The sharpening schedule has the details.
What is the best way to store gas over winter?
Two schools work. Either add a fuel stabilizer, fill the tank, and run the engine a few minutes so treated fuel reaches the carburetor, or run the machine completely dry so no fuel is left to varnish. Ethanol-blended pump gas is the troublemaker, drawing moisture and gumming up in a few months, so some owners switch to ethanol-free fuel for the last fill. The winterizing steps spell out both methods.
Do battery and robot mowers need any of this?
Far less, since there is no oil, spark plug, air filter, or fuel to fuss over. Battery mowers still need a sharp blade on the same schedule, a clean deck, and a battery stored around half charge in a cool, dry spot over winter rather than dead or full. Robot mowers add their own short list: keep the tiny blades fresh, clean the wheels and sensors, and check the boundary wire or GPS zone each spring.