A gas lawn mower needs an oil check before every mow, an oil change every 50 hours or once a season, a new air filter and spark plug each spring, a sharp blade, and stabilized fuel or an empty tank before winter. A battery mower skips the engine work but still needs a clean deck, a sharp blade and careful battery storage.
Lawn mower maintenance schedule#
| When |
Gas mower |
Battery mower |
| Before every mow |
Check oil level, look for loose or damaged parts |
Look for damage, check the battery is charged |
| After every mow |
Clear clippings from under the deck |
Same |
| First 5 hours of a new mower |
First oil change |
Not applicable |
| Every 50 hours or each season |
Change the oil |
Not applicable |
| Start of each season |
New air filter and spark plug, sharpen the blade |
Sharpen the blade |
| End of season |
Stabilize or run out the fuel, change oil, clean |
Clean, store the battery indoors |
The oil intervals come from Briggs & Stratton's engine maintenance guide. Your engine's own manual wins if it says something different, and Honda, Kohler and other engine makers publish their own schedules.
Before every mow#
Pull the dipstick and check the oil, ideally every time you mow, as Briggs & Stratton recommends. Top up to the fill line if it's low. Walk the lawn and pick up sticks, stones, dog toys and anything else the blade could throw. Look over the mower itself: a loose handle bolt, a cracked deck or a missing discharge guard should be fixed before you start it.
After mowing: cleaning the deck#
Wet clippings packed under the deck hold moisture against the steel and choke the airflow that lifts the grass, so the cut gets worse and the deck rusts from the inside.
- Stop the engine and wait for the blade to stop completely.
- On a gas mower, pull the spark plug lead off the plug. On a battery mower, take the battery out or remove the safety key.
- Scrape the packed clippings out from under the deck with a wooden stick or a plastic scraper. Keep your hands and feet away from the blade even with the power off, because it's sharp and can still turn.
- Brush clippings off the top of the engine and around the muffler. Briggs & Stratton's safety tips point out that debris built up there can cause overheating and fires.
Some mowers have a washout port where you attach a garden hose and run the engine to rinse the deck. Only hose down a mower that has one, or that the manual says can be washed, and keep water away from battery mower electronics.
To reach underneath, tip the mower only in the direction your manual shows. Tipping it the wrong way can let oil run into the air filter or fuel leak out of the carburetor.
Changing the oil, air filter and spark plug#
Change the oil after the first five hours on a new mower, then every 50 hours of use or at the start of each mowing season, whichever comes first. Unless you mow a big property, you're unlikely to hit 50 hours in a season, so in practice it's one oil change each spring. Drain the oil while the engine is warm, because warm oil flows out faster and takes more of the dirt with it.
Briggs & Stratton's spring maintenance parts list suggests starting each season with a new air filter and checking when the spark plug was last replaced. A dusty yard clogs a paper filter much faster, so check it mid-season if you mow dry, bare ground. A mower that's hard to start, runs rough or puffs black smoke often just needs a clean filter and a new plug.
How often to sharpen a lawn mower blade#
At least once a season, and more often if you mow a big lawn or hit a lot of sticks. A dull blade tears grass instead of cutting it, and you can see it a day or two later: the tips go ragged and turn brown or white, so the whole lawn looks faintly gray.
Take the blade off with the spark plug lead disconnected or the battery removed, and mark which side faces down before you remove it. You can sharpen it with a file or take it to a mower shop. Either way, the blade has to be balanced afterward. An unbalanced blade shakes the whole mower and is hard on the engine. If the blade is bent or cracked, or the mower starts vibrating after hitting a root or rock, stop and replace the blade before you use it again.
Storing a mower for winter#
Gas goes stale. Briggs & Stratton's equipment storage guide says gasoline starts to degrade in as little as 30 days. Stale fuel left in a small carburetor over winter can gum it up, and it's a common reason a mower won't start in spring. You have two options:
- Fill the tank, add a fuel stabilizer at the dose on the bottle, and run the engine for a few minutes so treated fuel reaches the carburetor. Briggs says treated fuel stays fresh for up to 24 months.
- Skip the stabilizer and run the engine until it stops from lack of fuel.
Then change the oil while the engine is still warm, clean the deck and engine, and store the mower somewhere dry.
Battery mowers are simpler, but the battery needs care. Take it off the mower and store it indoors. As one example, EGO's operator manual for its 56V zero-turn mower says to keep the brand's 56V packs in an enclosed space that won't drop below -4°F (-20°C), to charge them between 41°F and 104°F (5°C to 40°C), and to fully charge them every six months during long storage. Check your own brand's manual, since the numbers differ between manufacturers. You'll find the same pre-winter routine for spades and pruners in the garden tool cleaning guide, and the mower fits neatly into a broader winter preparation checklist.
Spring startup#
Fit the new filter and plug, check the oil, put the blade back on sharp, and give it fresh fuel if you ran the tank dry. Do it a couple of weeks before the grass needs cutting, so a mower that won't start goes to the repair shop before the spring rush. It's one of the first jobs on the spring home maintenance checklist for that reason, and an easy one to set as a yearly reminder in ChoreLists.com.