Skip to Content

How to Service a Lawn Tractor: Step-By-Step

You take pride in your home and keeping it in good condition. This includes giving your home a nice curb appeal. You purchased a lawn tractor to help you do just that. A lawn tractor is a significant investment. Protect your investment and extend its life by performing routine maintenance.

A full service on your lawn tractor includes changing the engine oil and filter; replacing the fuel filter, air filter, and spark plugs; replacing the hydraulic fluid if required; replacing or sharpening your mower blades; scraping the mower deck, and removing debris.

I have put together a list of items and steps required to service a lawn tractor.

How to service a lawn tractor

21 Steps to Service Your Lawn Tractor

1. Gather Tools & Materials

  • Tools (socket or spanner wrenches, filter wrench)
  • Engine oil filter
  • Engine oil
  • Spark plugs
  • Inner & outer air filter
  • Fuel filter
  • Rubber gloves, work gloves, and safety glasses
  • Plastic funnel
  • Rags or paper towel
  • Deck scraper or wire brush
  • Mower blades if not reusing current blades
  • Fuel stabilizer if preparing your lawn tractor for storage

2. Prepare the Lawn Tractor for Maintenance

Park your lawn tractor on a flat-level surface. To protect the ground from oil drips, place cardboard or newspaper under the tractor. Let your tractor run for a few minutes to warm the engine oil. Warm oil flows better than cold oil when draining the oil.

Shut your mower off. Remove the ignition key. Disconnect the spark plug wires on a gas-powered lawn tractor to prevent your mower from starting while you are working on it.

Set your parking brake. Refer to your owner’s manual for safety precautions to take with your model and type of lawn tractor.

3. Change the Engine Oil & Filter

Your lawn tractor will either have a drain plug or drain hose for draining oil. I prefer using an oil drain hose. It is easier to use and reduces oil spills.

The cap on the end of the hose can simply be twisted off. If your lawn tractor doesn’t use a drain hose, your engine manufacturer may offer one that fits your drain port. You can easily install a drain hose after draining the engine oil.

Place an oil drain pan under the plug or hose and proceed with the following steps to change the oil.

  • Remove the drain plug and allow the oil to run into the drain pan.
  • Remove your oil dipstick so the oil flows faster.
  • Reinstall the drain plug once the oil has completely drained.
  • Remove your engine oil filter and replace it with a new filter. Use a filter wrench to assist with loosening your oil filter. Place a light film of fresh oil on the seal of the new filter before installing it.
  • Add new oil to the engine until it is at the proper level. Use the oil dipstick to check for the correct oil level. It’s important to bring your oil level to the proper level and not overfill. Overfilling your crankcase can hurt your engine. If you do overfill the crankcase, you must remove a little oil.
  • Wipe off any spilled oil on your lawn tractor. Your tractor will smoke if spilled oil is left to burn off the engine once it gets hot. Properly dispose of your used engine oil at a recycling center. You can check with your local auto parts store to see if they accept used oil for recycling.

4. Check Spark Plug and Gap

Remove your old spark plugs using a 3/4” or 5/8” socket on a gas-powered lawn tractor. (A diesel lawn tractor does not use spark plugs). The size will depend on your engine manufacturer and model. Replace with new spark plugs so you are ready for the next mowing season.

Dirty spark plugs can cause starting and intermittent running issues when they start to fail. Don’t attach the spark plug wires until you have completed the service on your mower so it doesn’t accidentally start when you don’t want it to.

5. Remove Dirt & Debris from Your Cooling Fins and Engine Area

Your engine needs to be kept cool while it is running. Clogged cooling fins use the air circulating around the engine and the surface area of the fins to help dissipate heat. Remove any debris around your fins and the engine area.

6. Remove Dirt & Debris from Your Hydro Fans and Transmission Area

Most transmissions in lawn tractors today use a hydrostatic transmission. On residential lawn tractors, you will most likely find the transmissions are sealed and not serviceable.

Refer to your owner’s manual to confirm your transmission is not serviceable. Follow the direction in that manual to change and care for your transmission if it does allow you to change the hydraulic oil and filters.

The hydro fans keep your hydraulic transmission cool. Clean the dirt and debris from the fans and your transmission area to keep the area free of debris and in working order.

7. Clean Battery Terminals & Check the Battery

Make sure your battery terminals are clean and make a good connection. If they are showing signs of corrosion, clean them with a baking soda water solution consisting of 2 cups of water and 3 heaping tablespoons of baking soda. Use a wire brush to clean.

Check your battery to make sure it is fully charged. If it is not, place it on a trickle charger to make sure it is fully charged and will hold a charge. You will have to replace a battery that will not hold a charge. Read more about checking and charging your battery here.

8. Remove Debris Around the Electrical Components & Wiring

Check your electrical components and wiring for debris. Remove any debris you find. Debris can hold moisture and cause your electrical components to prematurely corrode and fail.

9. Replace the Air Filter

I typically replace my inner and outer air filters with new filters during a full service. The air filter is your first line of defense to prevent dirt from entering your engine and causing damage. It’s best to start each season with a new filter and clean it several times during the mowing season.

Find more about cleaning your air filter here.

10. Replace the Fuel Filter

Remove your fuel filter and replace it with a new filter. There should be an arrow on the side of your inline fuel filter indicating the direction of fuel flow. Install your fuel filter correctly using the arrow on the fuel filter.

11. Check the Fuel System for Leaks

Check over your fuel system to make sure all hoses are securely connected and there are no signs of fuel leaks. Leaks can develop when there are punctures or cracks in the fuel lines, components are not sealing correctly or plastics are degrading.

Repair all items that are leaking. Replace any fuel lines that are dry and cracking with new lines. For all areas to inspect for fuel leaks, check out this article.

12. Check the Tire Pressures

Check the tire pressures using a tire pressure gauge. Uneven tire pressures can cause your mower deck to sit unleveled giving you a bad cut. A low tire can also cause steering issues with your riding mower. Confirm your lug nuts are secure.

13. Remove the Mower Deck

It’s easiest to adequately clean and service the mower deck by removing the deck. Removing a mower deck from the lawn tractor can differ by manufacturer and tractor model.

Refer to your owner’s manual for instructions to remove components attaching your tractor to the deck so you can slide the deck from under the mower.

14. Remove Dirt and Debris on the Top of the Mower Deck

Remove dirt and debris from the top of your lawn tractor mower deck. Debris can get collect causing restriction in the movement of the tensioner bracket or hindering the movement of your belt along pulleys.

Make sure you get the debris removed from underneath the belt covers if your tractor uses covers.

The collection of dry materials on your deck can pose a fire danger. The heat from the friction of a deck belt can build up causing a potential fire hazard when combined with dry debris.

15. Check Pulleys and Belts

Now that your mower deck top is clean, make sure the pulleys and belts are in good condition. First, look at your belt. If it appears worn with a glazed shiny appearance; or it is cracked, stretched, or shredded, you must replace your deck belt.

Check your pulleys by slowly rotating them by hand. They should sit parallel to the deck and rotate smoothly. Replace the pulleys if you feel any resistance or hear noise coming from the bearing as you rotate the pulley.

If a pulley is rusty, clean the rust off the pulleys or replace it if it is very rusty. Rust can prematurely dry out the deck belt.

16. Scrape the Deck & Check the Blades

Gain access to the bottom of the mower deck on your lawn tractor

  • Check the bearings in your spindle housings for damage by grabbing a hold of each blade and rocking it up and down. When you feel movement or hear a knocking sound, remove your spindle housing and check for damage. Replace any bad bearings or replace the spindle housing assembly.
  • Replace your mower blades and replace with a new set. If your blades are in good condition and you choose not to replace them, sharpen and balance your blades before you install them.

    To find out more about when you need to replace or sharpen your blades read this guide on changing and sharpening your mower blades. Install your new or sharpened mower blades.
  • Scrape your mower deck to remove grass clippings and dirt using a deck scraper or metal brush. A clogged mower deck will affect your cut quality and cause your engine to work harder. The moisture in the debris can also prematurely corrode your mower deck.

17. Reinstall the Mower Deck & Check the Deck Level

Now that you are done with your mower deck maintenance, slide your mower deck back under your mower. Reattach your mower deck in the reverse order you took it off.

Adjust the Lawn Tractor Mower Deck Side-to-Side
With your mower deck on a flat level surface, adjust your deck lift to the middle position. Measure from the ground to the blade tip on the right side of the mower. Do the same on the left side of the mower.

If the two measurements are not the same, refer to your owner’s manual for instructions on leveling the deck as they vary by tractor model.

Adjust the Lawn Tractor Mower Deck Pitch Front-to-Rear
To adjust your mower deck pitch, first, start off by confirming your mower is on a flat level surface. Adjust your deck lift to the middle position.

With your blade parallel to the mower, measure from the ground to the blade tip on the front of the mower. Do the same on the rear.

Most lawn tractor mower decks are slightly lower, about 1/4” to 3/8” lower than the rear of the deck. Verify the pitch requirements in your owner’s manual and make adjustments as shown.

18. Check the Safety System

Your lawn tractor is equipped with a safety system. Follow the guide in your owner’s manual to make sure your safety system is working as it should. Skipping this step can compromise your safety. You never know when you are going to need it.

19. Replace Damaged, Worn, or Missing Parts. Secure Hardware.

Check over your tractor and replace all damaged, worn, or missing parts so your tractor is in good operating condition. All hardware needs to be securely in place.

20. Grease Lubrication Points

Grease your front wheels, front axle, and deck wheels. You will find a grease zerk on each of these items. Properly lubricate your lift linkages, pivot points, and brake to ensure they can move freely. I use high-performance grease and a spray lubricant.

21. Wash Your Tractor & Allow It To Dry Completely

Wash your tractor with a garden hose to clean any remaining dirt from the equipment. If you choose to use a pressure washer, do not use high pressure as this can damage sealed bearings. Once you are finished washing it, you need to let it completely dry.

I like cleaning my tractor on a sunny day if possible. Leaving it in the sun to dry allows the moisture around your electrical components and other areas of your mower to evaporate and completely dry.

Using a leaf blower to blow air on your mower can also assist with drying the mower. Any moisture left in the mower can cause premature corrosion of your mower’s components so you need to make sure every part of your tractor is dry.

If you need to move your mower to a different area for washing and drying, don’t forget to reattach your spark plug wires so your mower starts.

Do This if Your Lawn Tractor is Going into Storage for the Off-Season

  • Remove fuel from your gas tank OR add a fuel stabilizer to reduce gumming in your fuel system. Check out
  • Fully charge your battery so it does not freeze during storage OR remove and store it in a cool dry location.

Having Problems with Your Lawn Tractor?

It’s great to never develop a problem in your lawn tractor, but that is not the reality. Sooner or later you will experience an issue even if you regularly service it.

Because of this, I have put together the guide Common Lawn Tractor Problems & Solutions to help you know what to look for when your lawn tractor isn’t running right.