Home Outdoors Lawn

Lawn Tractor Maintenance Tips

Updated: Jul. 04, 2023

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Lawn tractor maintenance overview: Save $150 in one morning!

Lawnmower maintenance kit

The kit includes everything you need for basic lawn mower maintenance. A tube for a tubeless tire repair is extra.

Following the lawn tractor maintenance advice in your tractor’s manual is the best way to keep it humming along smoothly. But owner’s manuals usually only tell you basically what to do and when to do it—they seldom include the tips and real-world wisdom gained through experience. So we asked veteran mechanics which steps are the most important and how to make lawn tractor maintenance and tubeless tire repair faster and easier.

You’ll save money, too. Dealers typically charge more than $200 for routine lawn mower maintenance (like John Deere tractor service) that includes an oil change and new spark plugs and filters. But you can do all these things—and more—in just a few hours. A lawn tractor maintenance kit from your dealer (less than $75) might cost a few bucks more than buying parts separately but ensures that you get all the right stuff. And new tubes for a tubeless tire repair cost from $5 – $15.

Blow the mower deck clean

Clean the mower deck

Remove the belt guards and blow off the debris that wrecks belts and pulleys. Scrape away any debris buildup under the pulleys with a screwdriver.

Close-up of belt guard

Belt guards trap grass and debris that wears on the belts and pulleys.

You might think that the belt guards on top of a mower deck protect the belts and pulleys from grass clippings, dirt and other debris. But just the opposite is true. The spinning belts and pulleys suck in debris and the guards trap it inside. Then it swirls around, grinding away at the pulley surfaces and tearing up your belts. Once a pulley wears, it will quickly chew up every new belt you put on. Avoiding expensive belt and pulley replacements is easy; just blow the deck off with an air compressor or leaf blower after every third or fourth mowing.

Spark plug pointers

Change spark plugs

Spark plugs are the most important but least expensive components in the engine. Change them regularly for easy starting and fuel economy.

Worn spark plugs cause a variety of problems, from hard starting and poor fuel economy to misfires and even engine damage. So replace them at the manufacturer’s recommended intervals. Changing plugs is a simple matter of unscrewing the old ones and screwing in new ones. But there are a few things to keep in mind when doing this lawn mower maintenance project:

• Prevent debris from falling into the cylinder by brushing or blowing around the plug before you remove it. After removing the plug, wipe out the spark plug seat with a clean rag.
• If an old plug won’t turn, don’t resort to a bigger wrench. Brute force can cause major engine damage. Instead, use a spray that instantly cools the plug, causing the metal to contract and loosen. The spray is available at most auto parts stores or online (search for “CRC Freeze-Off”).
• Don’t forget to set the gap of the new plugs before installing them. Check the manual for gap specifications and use a gap gauge (from any auto parts store).
• Use just the right amount of force to tighten the plugs. If you don’t have a torque wrench, follow this general rule: First, finger-tighten the plug. If the plug has a gasket, tighten it an additional half turn using a plug wrench. If the plug has a tapered seat, tighten it an additional one-sixteenth turn.

Replace the fuel filter

Fuel filter technique

Replace the fuel filter without making a mess. Pinch off the fuel line with a clamp to stop any gas flow. As you remove the old filter, plug the openings with your fingers.

An old fuel filter can cause hard starting, poor fuel economy, maybe even an expensive carburetor rebuild. Check your owner’s manual to find out how often to replace the filter.

Replacing the fuel filter is easy. But there’s a trick to doing it without getting drenched in gasoline. First, pinch the fuel line leading from the tank with a clamp. Then move the spring clamps away from the filter with pliers. Slip on a pair of nitrile gloves, tilt the inlet side of the filter up and remove the inlet hose. Drain the small amount of fuel from the fuel line into a drain pan. Then, plug the filter inlet with your thumb, tilt the entire filter down, and pull it out of the outlet hose. This technique keeps most of the fuel inside the filter, reducing spillage. Place the old fuel filter in the drain pan and install the new filter. Pay attention to the fuel flow direction arrows—the arrow must point toward the engine. Move the fuel line clamps back into place and remove the “pinch-off” clamp from the fuel line.

Tip: Get a smaller gas can. Old gas (stored for more than 30 days) is the most common cause of starting problems.

Choose the right oil

Replace the oil filter

Screw on the new oil filter until the rubber gasket touches the seat. Then give the filter another half turn. Spread a light coat of oil on the gasket so it doesn’t bind against the seat.

Check the oil grade stamp

Check the “donut” on the back of the container and be sure to buy oil with an “SM” rating.

Just like your car, your tractor needs regular oil changes. If your owner’s manual suggests a brand of oil, you can ignore that advice. But do pay attention to the recommended viscosity (such as 10W- 30) to find the best type of oil for your mower. If you use your tractor for snow removal, check the manual for a “winter weight” oil recommendation. Never, ever change the oil without also changing the oil filter. To prevent a buildup of gunk on the engine, wipe up any spilled oil. Bottle the old oil and take it to your nearest oil recycling center for disposal.

Blade-changing tips

Photo 1: Loosen stubborn bolts

Loosen stubborn blade bolts with a long breaker bar. Hold back the blade with wood blocks and a C-clamp. A clamp on the rear wheel stops the deck from rolling as you flip it over.

Photo 2: Install new blades

Position the new blades in a “U” pattern for better balance and less vibration. Tighten blade bolts with a torque wrench to avoid breaking them.

Dull blades make the engine and belts work harder. They’re bad for your grass, too. Instead of slicing off the grass cleanly, they leave a torn edge that takes longer to heal.

• To change blades safely, remove the mower deck instead of working from underneath the tractor.
• If the deck has wheels, it tends to roll away as you try to flip it over. Lock one wheel with a clamp as shown in (Photo 1) above. Lay the deck on a couple of 2x4s to prevent damage to the pulleys.
• Lock the blades in place with a clamp and blocks as shown. Don’t simply wedge a block between the blade and deck; the blade can break free and cut you.
• If you’re an Olympic weightlifter, you can loosen the blade bolts with an ordinary wrench or ratchet. If not, use a 25-in. breaker bar and six-point socket (about $25 for both at home centers and hardware stores).
• Blade changes are less hassle if you keep a spare set handy. You can sharpen the dull ones in your spare time or take them in for professional sharpening. For sharpening tips, type “mower blade” in the search box above. Learn how to sharpen mower blades with an angle grinder.
• Grass buildup on the underside of the deck reduces cutting efficiency. Scrape off big chunks with a flat pry bar and clean up the rest with a putty knife.
• To avoid over-tightening blade bolts, check the specs in the owner’s manual and use a torque wrench (about $50 at home centers and hardware stores). Truth is, many tractor owners get by without a torque wrench. But if you ever break a bolt, remember that we warned you.

Tip: Cutting tall grass is very hard on belts. If you’ve let the grass go too long between cuttings, mow in half swaths to reduce the load and extend belt life.

Clean the air filter between changes

Clean the filters

Wash the foam prefilter and blow off the filter at least once a month during the dusty mowing season.

You already know that it’s important to change the air filter as often as the owner’s manual recommends. But it’s also a good idea to clean the filter between changes. If your tractor has a foam prefilter, wash it with soap and water; never use a solvent or other cleaner. Blow out the pleated paper filter with a light blast from an air compressor. Keep in mind that this is not a substitute for regular filter changes. Even if the filter looks clean, replace it with a new one at recommended intervals.

Grease guidance

Add new grease

Pump grease into the fitting until all the dark old grease is purged and fresh new grease oozes out.

It isn’t exactly rocket science, but many tractor owners goof up greasing. The biggest mistake is using the wrong grease. The brand doesn’t matter, but use the type recommended by the manufacturer, whether it’s plain lithium, lithium with molybdenum disulfide, or poly urea. Grease every fitting every time you change the oil. Check your owner’s manual to locate them all. There may be grease fittings on your mower deck and other attachments too. A flexible hose makes reaching the fittings a lot easier. Pick up a grease gun and hose at any home center or auto parts store (about $25 for both).

Fix tubeless tire leaks

Photo 1: Break both beads

Cut a 45-degree angle on a short piece of 2×2. Place the angled edge right where the tire meets the steel wheel. Then smack it with a maul to break the tire bead away from the wheel. Move the 2×2 around the entire edge until the bead is completely detached. Flip over the wheel and break the bead on the opposite side.

Photo 2: Pry off the tire

Pry the tire bead up with a large screwdriver. Hold that part of the tire away from the wheel and use a second screwdriver to pry up another section. Repeat until the entire bead is off.

Photo 3: Pry the tire back onto the wheel

Once the inner tube is in place, hold the valve stem with a spring clamp. Then slide the round handle ends of two large adjustable wrenches (a screwdriver will puncture the tube) under the bead and pry it up and then back onto the wheel.

Got a garden tractor tire that’s always low and you can’t find a puncture? Chances are you’ve got a bead leak caused by a rusting wheel. You can yank the tire, remove the corrosion from the wheel with a wire wheel and then paint it, but my guess is that the tire will still leak air. That’s way too much trouble to wind up back where you started. Just install an inner tube and put an end to deflated tires. Write down the tire size and buy the same size tube.

Start by cutting off the old valve stem with a side cutters or utility knife. Next, break the bead (Photo 1). Slide a large screwdriver or pry bar down the center of the wheel and clamp it in a vise. Then pry the bead off the wheel (Photo 2).

Rotate the inner tube so the valve stem lines up with the valve stem hole in the wheel. Tuck the inner tube inside the tire and pull the valve stem through the hole. Secure the valve stem with a spring clamp. Then pry the tire bead back onto the wheel and reinflate (Photo 3).

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration while doing lawn mower maintenance.

• Breaker bar
• Clamps
• Grease gun
• Hammer
• Oil filter wrench
• Screwdriver
• Shop vacuum
• Side cutter
• Socket/ratchet set
• Spark plug socket
• Torque wrench

You’ll also need nitrile (plastic) gloves and a spark plug gap gauge.

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.

• Maintenance kit