Lawn Mower Maintenance: Keep It Running for Years
To maintain a lawn mower, keep the blade sharp and balanced, change the oil and clean or replace the air filter each season, check the spark plug, and clear grass from under the deck after mowing. On battery mowers, care for the pack and blade instead. A little regular upkeep keeps the machine starting easily and cutting cleanly.
A lawn mower will give you years of easy starts and clean cuts if you look after it, or turn into a frustrating, smoking, hard to start chore if you never open it up. The good news is that mower maintenance is simple, cheap and quick once you know the handful of parts that need attention.
This routine covers gas and battery mowers alike, so you can keep yours running its best whatever you own. Good upkeep also prevents most of the faults in our list of common lawn mower problems, and it protects the value of a machine you may one day replace from our best lawn mowers roundup.
Safety first, every time
Before you touch any moving part, make the mower safe. This one habit prevents the most serious garden injuries, and it takes only a moment.
- On a gas mower, disconnect the spark plug lead so the engine cannot fire.
- On a battery mower, remove the battery and any safety key.
- Let the engine and deck cool, and close the fuel before tipping a gas mower.
Wear sturdy gloves when handling the blade, and tip the machine the way the manual shows, usually with the air filter and spark plug facing up, to avoid oil and fuel leaks.
Keep the blade sharp and balanced
The blade does the actual work, and its condition shows in your lawn. A sharp blade slices cleanly, while a dull one tears the grass, leaving ragged, pale tips that brown off and invite disease. Most lawns benefit from sharpening the blade once or twice a season, more if you hit the odd stone.
You can sharpen a blade with a file or bench grinder, keeping the original angle, or have it done cheaply at a hardware store. Just as important is balance. A blade sharpened unevenly wobbles, which causes vibration and wears the engine bearings, so check it hangs level on a nail through the centre hole before refitting. Replace any blade that is cracked, deeply notched or bent.
Oil, air filter and spark plug
Gas engines ask for a little seasonal service, much like a car in miniature. Skipping it is the main reason mowers get hard to start as they age.
- Oil: check the level before each use and change it at the start of the season, or as the manual says, since dirty oil wears the engine.
- Air filter: a clogged filter starves the engine and causes rough running, so clean a foam filter or replace a paper one yearly.
- Spark plug: a fresh plug each season gives easy starts and smooth running for very little money.
None of these jobs takes long, and together they make the difference between a mower that fires on the first pull and one that fights you.
Clean under the deck after mowing
Grass clippings pack under the deck, especially when the lawn is damp, and that matted layer chokes airflow, reduces cutting quality and holds moisture against the metal until it rusts. Clearing it is one of the most useful habits you can build.
With the mower made safe and tipped correctly, scrape the underside with a plastic tool or a stiff brush until the deck is clear. Doing this while the clippings are fresh is far easier than chipping off a dried crust weeks later. A clean deck cuts better and lasts longer, which links directly to how often you cut, a topic we cover in how often you should mow your lawn.
Battery care and off season storage
Battery mowers need less work, but the pack still wants sensible care. Store it indoors at room temperature, avoid leaving it fully flat or in freezing cold, and keep the terminals clean. The blade, deck and wheels still need the same attention as any mower.
For gas mowers, the end of the season matters most. Either run the tank dry or add fuel stabiliser before storage, since stale fuel gumming the carburettor is a top cause of a no start next spring. Store the machine somewhere dry, and it will be ready when the grass starts growing again. If your mower is past saving despite good care, our best lawn mowers roundup and wider Outdoors & Garden guides can help you choose well.
Ready to pick one?
If regular upkeep is no longer keeping your mower going, see our current top picks for every size of lawn.
Frequently asked questions
How often should I sharpen my mower blade?
Once or twice a season suits most lawns, and more often if you hit stones or mow rough ground. A sharp blade slices cleanly, while a dull one tears the grass and leaves pale, frayed tips, so check it whenever the cut starts to look ragged.
When should I change the oil in my lawn mower?
Change a gas mower oil at the start of each season, or as the manual specifies, and check the level before every use. Fresh oil keeps the engine running cool and smooth, while old, dirty oil is a common reason mowers get harder to start with age.
How often should I replace the air filter?
Clean a foam air filter regularly and replace a paper one about once a year, more often in dusty conditions. A clogged filter starves the engine of air, causing rough running and hard starting, so it is one of the cheapest, easiest parts to stay on top of.
Should I run my mower out of fuel for winter?
Either run the tank dry or add a fuel stabiliser before storing a gas mower for the off season. Stale fuel gumming the carburettor is a top cause of a no start in spring, so one of these steps saves a frustrating job when the grass returns.
How do I clean under the mower deck?
First make the mower safe by removing the spark plug lead or battery, then tip it the way the manual shows and scrape the underside with a plastic tool or stiff brush. Doing it while clippings are fresh is far easier than chipping off a dried, rusty crust later.
Do battery mowers need maintenance?
Yes, just less. There is no oil, filter or spark plug, but you still keep the blade sharp, clear the deck, and care for the battery by storing it indoors at room temperature and not leaving it fully flat or frozen. The basics still keep it cutting well.
Why does my mower get harder to start over time?
Usually it is neglected servicing rather than a worn engine. Stale fuel, a dirty air filter, a tired spark plug and old oil all make starting harder. A quick seasonal service of these parts brings most mowers back to firing on the first pull.