Lawn Mower Maintenance

A lush, well-trimmed lawn can greatly enhance the curb appeal of any home. To ensure your lawn mower starts quickly, runs smoothly and cuts cleanly throughout the spring and summer, perform a preseason checkup that includes engine maintenance and parts inspection.

Fortunately, lawn mower maintenance doesn’t require a huge investment in time or money, and no special mechanical ability is needed. Armed with a little know-how and a few simple tools, you can keep your lawn mower going all season. Plus, regularly performing these maintenance chores helps avoid costly repairs and extends the life of the mower by many years.

For specific maintenance questions about your Cub Cadet, Troy-Bilt, Toro, Husqvarna mower, or any of our Tractor Supply lawn mowers, refer to your owner’s manual, contact the manufacturer or visit your local Tractor Supply Co. store.

How to tune up a lawn mower in the spring

While it might be tempting to just roll your mower out of winter storage and start yanking on the cord, your mower will perform much better if you follow these spring lawn mower tune-up steps first:

1. Refuel with fresh gas

Never use gasoline that’s more than a month or so old. Old gas clogs fuel lines, gums up the carburetor and prevents the engine from starting. To ensure the gas tank, fuel lines and carburetor are clean of gas and ready for fresh fuel in the spring, let your mower run out of gas before storing it for the winter. Alternatively, you can add a fuel stabilizer to the gas tank, which will keep the fuel fresh.

2. Change the oil

Running the engine with dirty or low oil shortens the life of the engine and, in extreme cases, causes the engine to seize up permanently. Change the mower oil at the start of each season using the precise type and weight of motor oil recommended by the manufacturer. Check the oil level every time you start the engine and always recycle used oil at a licensed oil collection location or your local Tractor Supply store.

3. Check the fuel filter

The fuel filter strains out foreign particles. A dirty fuel filter also causes the engine to run too lean, making it difficult to start. Clean or replace the fuel filter every year.

4. Install a new air filter

Lawn mowers kick up clouds of dust and dirt, which can be sucked into the engine’s combustion chamber, causing problems like poor fuel efficiency, hard starting, rough running and shorter engine life. So, it’s important to either clean the air filter or install a new air filter each spring.

5. Inspect the spark plugs

Changing a lawn mower spark plug that’s worn down, dirty or damaged keeps the mower’s engine running smoothly. Before cranking up the engine for the first spring mowing, remove and inspect the spark plug.

• Pull the hooded electrical cable off the spark plug.
• Prevent accumulated gunk from falling into the engine by using a small brush to clean the area around the spark plug.
• Remove the spark plug using the correct-size spark plug wrench.
• Check it carefully to make sure the white porcelain isn’t cracked or the tip of the electrode at the base of the plug hasn’t burned away. Discard the spark plug if you see any damage and replace it with one recommended by the manufacturer.

An undamaged spark plug can be reused. Follow these steps:

• Clean the electrode with a wire brush.
• Use a feeler gauge to check the spark-plug gap. Look in the owner’s manual for the proper gap distance; most spark plugs require a gap of either .020 inch or .030 inch.
• Hand-thread the spark plug back into the engine, being very careful not to cross the threads.
• Tighten the spark plug. Be careful not to over-tighten, or it’ll crack.

1. Grease the mechanical joints

Poorly lubricated joints, linkages and other moving parts can prematurely wear out or seize up and stop functioning. Consult the owner’s manual for the location of all the grease fittings and use a grease gun to squeeze grease into each fitting. You’ll know when to stop squeezing when you see grease oozing out of the joint.  

2. Recharge the battery

If your lawn mower has a battery, it’ll often die or lose power after sitting idle all winter. You can usually recharge a dead battery to full strength, but if that doesn’t work, you’ll need to replace it with a new battery.

Before placing the battery back into the mower, use battery cleaner to clean the positive and negative terminals. After installing it, spray a coating of battery protector onto the cable clamps and terminals to prevent corrosion and ensure a good electrical connection for easy starting. 

Winter mower maintenance tips

If you complete the maintenance chores listed above every spring, your mower will run smoothly throughout the entire mowing season. When fall arrives, you should winterize the mower before putting it to bed for the season. It may be tempting to just roll the mower into the garage and worry about it next year, but procrastinating will only make it much more difficult to get the mower up and running come spring. For best results, follow these specific end-of-season lawn mower maintenance tips for winterizing your mower:

1. Empty the gas tank

As mentioned earlier, it’s best to empty the mower of fuel by letting the engine run out of gas. Draining or siphoning the tank dry doesn’t remove the gas trapped in the fuel line and carburetor. If you added a fuel stabilizer, drain the tank, and save the gas until next spring, or run it in your snowblower.

If the gasoline drained from the mower doesn’t contain a stabilizer, use it as soon as possible. Storing the gas all winter will cause the ethanol to separate and its other chemical components to degrade.

Finally, to ensure the mower is as fuel-free as possible, disconnect and drain the fuel lines.

2. Remove the spark plug

Remove the spark plug. Spray a shot of penetrating oil into the cylinder, and pull the recoil handle a few times to ensure the oil is evenly distributed on the wall of the cylinder. Carefully thread the old spark plug back into the hole. If it’s damaged, swap it out with a new one.

3. Clean the lawn mower

At the end of the mowing season, the underside of the mowing deck will be coated with a thick layer of caked-on grass clippings that can cause rust. Scrape off the clippings in the fall—if you leave them on until spring, the clippings can dry into a hard, impenetrable mass. To clean the mowing deck:

• Disconnect the ignition wire from the spark plug to prevent accidental starting.
• Raise the mowing deck as high as possible or securely prop the mower up onto its side.
• Reach under the mower and use a stiff-blade plastic putty knife or thin wooden stick (try a paint stirrer) to scrape off the matted grass. Don’t use a metal tool, or you might scratch the underside of the mowing deck and expose the metal to rusting. 

If your mower has fabric grass-collection bags, use a soft-bristle scrub brush or wet/dry vacuum to clean off clippings and debris. Clean plastic collection bins with a garden hose and long-handled scrub brush. Don’t forget to clean the inside of the large diameter suction tube, too.

Hose down the outside of the mower but be careful not to spray water directly into the engine. Wipe the mower dry with an old towel before storing it away.

If your mower needs a deep clean, this guide to cleaning your lawn mower can walk you through how to clean each part, including ride-on mowing attachments.

4. Sharpen the blade

It’s important to sharpen the lawn mower blade at least once a year. A dull blade rips through grass and leaves torn tips on the ends of the blades, causing the grass to turn brown and leaving your lawn susceptible to disease and pests. On the other hand, a sharp blade cuts grass quickly and cleanly, resulting in a neatly trimmed, healthier lawn.

Caution: If the blade is bent, chipped or cracked, you must replace it with a new blade.

You can sharpen a lawn mower blade with a bench grinder, hand file, rotary tool or angle grinder. However, a drill and sharpening stone that’s specifically designed for sharpening lawn mower blades is the fastest.

Depending on your mower’s design, you might be able to sharpen the blade without removing it. However, removing the blade gives you easier access to the cutting edges and permits better visual inspection for damage, such as stress fractures and excessive wear. Our guide on how to remove a lawn mower blade can help ensure you do it safely and correctly,

5. Remove the battery

For lawn tractors, remove the battery, and store it inside over the winter. Clean away any grease or dirt and store it in a cool, dry location. Make sure it’s away from flammable substances like gasoline or heat sources like a water heater or furnace. Come springtime, use a 120-volt battery charger to bring the battery to full capacity and reinstall it. The same goes for a cordless, battery-powered mower: remove the battery and store it indoors.

6. Final winter storage tip

Store the mower inside a garage or shed and cover it with a tarp to protect it from dust. Place tamper-resistant, pet-safe bait stations under the mower to discourage mice from chewing the electrical wiring and bedding down inside the engine compartment. You can also spray the mower with peppermint oil mice repellent—mice hate the smell of peppermint.

Knowing how to start a lawn mower typically isn’t enough to keep your mower running smoothly all year. Use this lawn mower maintenance checklist as a template for your schedule, so your yard equipment stays in tip-top shape in every season.