You are at the end of the mowing season and need to get your riding lawn mower prepared for storage. You want to make sure nothing gets missed so your lawn mower doesn’t develop problems before next season.

To winterize your riding lawn mower, you must remove debris; scrape the deck; wash and remove moisture from mower components; change the engine oil; fully charge or remove your battery; and add fuel stabilizer to your gas tank before storage. 

Read on and I’ll share the steps you need to take to winterize your riding lawn mower before placing in a dry storage area.

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Follow all safety instructions provided in your equipment operator’s manual prior to diagnosing, repairing, or operating.Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.

Winterize Your Riding Lawn Mower 

Gather Tools and Supplies 

• Mower deck scraper, metal putty knife, or wire brush 
• Gloves and rags 
• Fuel stabilizer to add to fuel or a gas container if you are draining the fuel from your tank
• Oil Change Supplies: Oil, Filter & Filter Wrench, Socket or Spanner Wrenches, and Drain Pan

You may want to add cardboard or another item to lay on the ground to keep oils from penetrating the work surface. 

Remove Debris, Wash and Dry Riding Mower 

Brush large collections of grass and debris from the mower. Use a garden hose to spray off the lawn mower to remove dirt from the mower. Be careful if you choose to use a pressure washer.

You should not use high pressure near the riding mower’s bearings. Even though bearings are often sealed, they are not sealed from high pressure. 

If you have a deck wash port, follow your manufacturer’s instructions to attach the hose and engage the mower blades to wash the bottom of the deck. 

You do not want to store your mower with any moisture in the mower’s components. I prefer to let my mower set outside in the sun on a breezy day to let the moisture evaporate. I know every day is not sunny so you may not have that option on the day you choose to winterize your riding mower. 

You can use a handheld blower to help completely dry the lawn mower and its components. Storing your mower with moisture can cause premature rusting of the metal and corrosion of your electrical components. 

Change Your Riding Mower’s Engine Oil  

It’s good to change your oil at the end of the season so you are ready for the next mowing season.  

• Park on a flat surface (on top of your cardboard if you choose to cover the surface). Warm the engine for a couple of minutes. Oil flows better when it is warm. 
• Shut off the mower, remove the key and disconnect the spark plug lead from the spark plug(s) for safety before you begin your oil change. Do not skip this safety step. Also, be careful when working around the engine as it can be hot. 

• Drain engine oil and remove the filter. You will find a drain plug near the bottom of your engine.
• Replace the new filter by first placing a light film of oil over the seal and attaching it to the engine. 
• Fill with oil according to your manufacturer’s instructions. Make sure you use the correct oil and quantity of oil. You do not want to overfill the engine. Read the damaging effects this can have on the engine: “7 Things That Can Cause An Engine to Overheat“

Scrape Your Riding Mower Deck 

Prop your mower deck up by using jack stands or another comparable item. Be careful using pneumatic stands as they can shift and put you in a very dangerous position.

If you are unable to get enough height to reach under your mower deck you may need to remove the deck from the lawn tractor. Refer to your owner’s manual for instructions

Once you have access to the underside of the mower deck, you will want to scrape the deck using a deck scraper or a small putty knife. A wire brush will work as well. Remove the debris from the deck. Grass can hold moisture that can prematurely rust your deck.  

It is a good idea to check your blades and inspect the bearings in the cutter housings while you have your deck elevated. If you need help knowing what to look for and how to tell your bearings are bad, read this article. 

Add Fuel Stabilizer or Drain Your Fuel Tank  

While many riding lawn mower owners choose to drain their fuel tanks for storage during the winter season, I choose an easier option and add a fuel stabilizer to the existing gas.

Either option is okay. Leaving untreated fuel sitting in your lawn mower over the winter can cause problems with the fuel system. 

Drain Your Fuel Tank 

You will need to siphon fuel out of the fuel tank and into an approved fuel container. (Do not use containers that are not suitable for fuel storage as the materials in some containers can break down).

Once you have removed as much fuel as possible, start the lawn mower and burn the rest of the fuel out of the system. Let it run until it shuts off and no longer restarts. 

Add Fuel Stabilizer 

If you choose the option to store your mower with the fuel you must use a fuel stabilizer. Without a fuel stabilizer, the old fuel can cause gumming and varnish build-up in the fuel system. The ethanol used in the fuel will collect moisture. 

I highly recommend a product called Sea Foam Motor Treatment. This product will not only stabilize your fuel for up to two years but also assist with removing moisture. I have more information on Sea Foam as a fuel additive in my article, “Why Use Sea Foam Fuel Additive in a Lawn Mower”. 

Add the appropriate amount of Sea Foam to the amount of fresh gas in your fuel tank. Start the engine and let it run for a few minutes so the treated fuel will work its way through the fuel system. 

Remove the Battery and Clean Terminals 

You also have an option when it comes to storing your battery during the winter. When your battery is fully charged, it will not freeze. If you choose to keep the battery installed on your riding mower, you must make sure it is fully charged.

Many riding mower owners want to make sure their battery does not freeze so they choose to remove the battery and store it in a cool dry place. They don’t always trust their skills at making sure their battery is in a fully charged state.   

If you choose to remove your riding mower battery, follow these steps: 

• Take the necessary precautions to cover your eyes and body from battery acid by wearing eye protection and gloves 
• With the engine turned off, remove the brackets or bungee straps that are holding the battery in place
• Using an adjustable wrench, turn the black negative terminal counterclockwise to loosen it and remove the cable
• Follow the same procedure with the red positive terminal as you did with the negative terminal
• Store the battery away from combustible items and in a cool dry location 

For a more in-depth article read my “Guide to Winter Lawn Mower Battery Care“.

Use a Rodent Prevention Method Around Your Riding Mower 

Too many times in my position at the independent lawn mower and tractor dealership I worked, I saw the damage rodents can do to a piece of equipment.

Sometimes the dead rodents are still in the filter housing, radiator, or tangled in the wiring harness when the equipment is brought into the repair shop. 

Rodents like to make nests in riding mowers and chew on their wires. The damage from a rodent infestation can end up being a costly repair. I add products to my lawn mower to prevent this from happening to me. 

I use a product called Grandpa Gus’s Mouse Repellent. I love that it smells a whole lot better than using mothballs. It is an all-natural product and comes in the form of packets and liquid spray. 

I place the packets around my mower and use the liquid spray on the wires to keep the hungry rodents from chewing on them. 

These products don’t only work well on riding mowers, my friends and I also use them in our campers, motorcycles, tractors, and cars that are stored for long periods of time.  

Store Riding Lawn Mower in a Dry Cool Place 

Your riding mower should be stored in a cool dry place. Cover your mower with a tarp or large drop cloth to keep the dust off the lawn mower when storing it inside.

If you don’t have any choice but to store your mower outdoors, you need to cover it with a waterproof covering like these marine-grade coverings from Amazon.