Lawn Tractor Maintenance Tips

Replace the fuel filter

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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.

Zero-turn mower

Lawn tractor mower

Other Lawnmower Models

We show a John Deere tractor in this story, but the maintenance is similar for other brands. Just be sure to follow the procedures, service intervals, and lubricant and torque specifications shown in your owner's manual.

Zero-turn mowers
“ZTR” mowers have a hydraulic steering system, requiring you to change the hydraulic fluid and filter occasionally (typically every 300 hours). It's a quick, simple job, a lot like changing the motor oil.

Service schedules
Every manufacturer recommends different “service intervals” for things like oil, filter and spark plug changes. These intervals can vary a lot. Many manufacturers recommend greasing moving parts every 50 hours, but some call for it every 25 hours. So don't follow general guidelines—follow your manual.

Choose the right oil

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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.

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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). 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

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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.

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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.
• 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

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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.

Cover the air intake and exhaust openings with plastic
wrap or aluminum foil to keep critters from
homesteading in your engine over winter.

3 Easy Winterization Steps

Before your tractor hibernates for the winter, take a few minutes to prevent springtime troubles.

1. Moisture inside an unused engine leads to corrosion. “Fogging“ the engine—spraying an oily mist into each cylinder—prevents this. All you have to do is remove the spark plugs and blast in some aerosol fogging spray (at auto parts stores). Then reinstall the spark plugs.
2. Storing a battery that isn't fully charged can lead to permanent damage, especially in cold weather. Connect the battery to a battery charger and charge it until you get a reading of 12.7 volts.
3. Stored gas will slowly gum up the whole fuel system, and the repairs can be expensive. So add a fuel stabilizer such as STA-BIL or Seafoam (at auto parts stores) to the gas tank before winter. (Adding stabilizer to your gas can year-round is also a good idea.) But remember that stabilizers aren't effective in gas that contains ethanol. If you don't know whether the gas contains ethanol, run the engine until the tank is empty.

Grease guidance

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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

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Photo 1: Break both beads

Cut a 45-degree angle on a short piece of 2x2. 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 2x2 around the entire edge until the bead is completely detached. Flip over the wheel and break the bead on the opposite side.

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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.

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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).