How to Winterize a Lawn Mower


Winterizing your lawn mower is an essential maintenance task that will keep your mower running smoothly when spring rolls around. Neglecting to winterize can lead to a number of problems including corrosion, stale gasoline, and seizure of the engine. Properly preparing your mower for storage over the winter months will save you time and money come spring.

In this comprehensive guide, we will walk through all the steps needed to properly winterize any gas-powered push or riding lawn mower. We will cover draining fuel, changing oil, lubricating parts, removing the battery, sharpening blades, and protecting the deck. With a few tools and supplies on hand, you can complete the winterization process in an afternoon. Follow along and we’ll make sure your mower is ready for next year’s mowing season.

Steps to Winterize a Lawn Mower

Clean the Mower Thoroughly

The first step is to clean your mower thoroughly before storage. Remove all grass clippings, dirt and debris from the underside of the deck, around the engine and on mower surfaces. Use a stiff brush and shop vacuum if needed.

Be sure to inspect the underside of the deck and remove any buildup of grass or dirt around pulleys, belts and spindles. Buildup in these areas can cause problems when mowing next season if left all winter.

Wash the mower body with a garden hose to remove caked on dirt or grass. Wipe down any metal surfaces with a clean cloth. Avoid spraying water directly at the engine or electrical components.

Thorough cleaning will allow you to inspect the mower fully and help prevent corrosion or damage over the winter months.

Drain the Fuel

Perhaps the most important winterizing task is to drain all the gasoline from the fuel tank and carburetor.Gas that sits unused over several months will start to degrade, which can lead to serious starting issues come spring.

Use a siphoning kit to remove all fuel from the tank, or place a fuel stabilizer like Sta-Bil in the tank and run the mower for 10 minutes to circulate it before draining. The stabilizer will keep the gasoline fresh for storage.

Once drained, reattach the fuel line and start the mower for 30 seconds to use up any remaining gas in the carburetor.

Tip: Place an empty metal gas can under the fuel line to catch any drained gasoline for disposal or reuse in your car. Never store old gas in a plastic gas can.

Removing old fuel is the most effective way to avoid carburetor or engine problems after storage.

Change the Engine Oil

Changing the engine oil is another critical winterizing step. Old oil left in the crankcase over several months can lead to corrosion and the formation of harmful deposits.

Refer to your owner’s manual for the oil type and capacity needed for your mower’s engine. Most take 20-30oz of standard motor oil like 10W-30. Drain the old oil through the dipstick tube or a separate drain plug.

Refill with fresh oil up to the “full” mark on the dipstick. Dispose of the drained oil properly at a recycling center, never pour down a drain.

Changing the oil will remove built-up contaminants to prevent internal engine damage over the winter.

Lubricate Moving Parts

Lubricating any moving metal parts will prevent rust formation while in storage. Wipe down and apply lubricant to these key areas:

  • Blade control lever joints
  • Throttle and choke control cables
  • Wheel axles
  • Shift lever pivots
  • Brake levers

Use a lightweight machine oil or lubricant spray to penetrate joints and coat metal surfaces. Wipe away any excess.

Lubrication protects critical moving components from seizing up after months of non-use.

Remove the Battery

For riding mowers, remove the battery and store it over the winter to maintain its charge.

Clean the battery terminals and cables using a wire brush to remove any corrosion. Then disconnect the battery cables or removal strap. Store the battery in a cool, dry place and place it on a trickle charger or charge monthly to maintain the charge level.

Removing the battery will extend its life and prevent costly replacement in the spring. Charge over winter to avoid starting issues.

Sharpen the Blades

The end of mowing season is the perfect time to sharpen your mower’s cutting blades. Using a file or grinding wheel, give each blade a fresh edge so they will be ready for peak cutting performance next season.

Remove each blade from the underside of the deck to sharpen fully. Refer to your manual for proper blade removal.

Check blades for signs of wear like large nicks or gouges which would require blade replacement.

Sharpening in fall means your mower will cut clean and even from the first spring mow.

Coat Metal Surfaces

To combat moisture, rust and corrosion, coat any exposed metal surfaces with a protectant spray. Painted metal surfaces are also susceptible to chips and rust over winter.

Focus on applying protectant to:

  • Deck underside
  • Engine and carburetor
  • Pulleys, gears and levers
  • Battery terminals
  • Muffler and exhaust system

Use a rust-inhibiting spray like WD-40 or a dedicated protectant like Fluid Film. Apply a thin coat and wipe any drips or overspray.

Protecting metal components will minimize rust issues after sitting unused over winter.

Clean Air Filter

Check and clean the engine air filter before storage to promote easy starting in the spring. Remove the filter and tap out any dirt or debris, being careful not to damage the filter element.

You can wash foam filters in warm soapy water and rinse thoroughly. Allow to fully dry before reinstalling.

For pleated paper filters, gently blow out dust using compressed air or replace the filter if very dirty.

Tip: Mark your replacement date on new air filters to maintain the schedule.

A clean filter allows proper air flow to the carburetor and engine when restarting the mower.

Inflate the Tires

Check the tire pressure before storage. Inflate each tire on rider and push mowers to the recommended pressure listed on the sidewall of the tire.

Low pressure over several months can cause sidewall damage. Use a portable air compressor or service station pump to fill the tires.

Properly inflated tires will prevent flat spots from developing while in storage.

Clean the Mower Deck

For the underside mower deck, scrape away packed grass clippings, dirt and debris with a putty knife or wire brush. Buildup left on the deck shell over winter can lead to rust and corrosion.

Once scraped, wipe down the deck with a cloth dampened with water or a degreasing solution. Apply a protectant spray to deter rust.

Remove grass from the discharge chute as well. Seal any gaps or holes on the deck with silicone caulk to prevent moisture entry.

Cleaning under the deck will reveal any rust issues that need to be addressed before storage.

Change the Spark Plug

The spark plug is vital for easy starting after sitting idle. Old or failing plugs should be replaced at the end of the mowing season

Use a spark plug wrench to remove the old plug. Check for signs of wear like a cracked porcelain insulator. Gap a new plug to the spec in the owner’s manual, commonly .030 inches.

Install the new properly gapped plug by hand threading it first to avoid cross-threading. Tight tighten with the plug wrench to compress the gasket.

A new spark plug ensures reliable ignition when restarting your stored mower.

Top Off Fluids

Check all other fluid levels before winter storage including:

  • Engine oil: Top off to full mark on dipstick
  • Transmission oil: Add through reservoir cap if low
  • Hydraulic oil: Fill hydraulic reservoir if low
  • Fuel: Add fresh gasoline treated with stabilizer

Topping off fluids prevents leaks and damage over the winter and saves you service time in the spring.

Apply Protective Covers

For additional winter protection, cover your mower with a breathable material like a canvas tarp. Avoid using plastic sheeting which can trap moisture.

Secure the cover so it does not flap loose over winter.

For the mower deck, cover just the top and not the underside which needs ventilation to prevent moisture buildup leading to rust.

Use tie-downs, ropes or bungee cords to keep covers in place over the winter months.

Store Mower Properly

The final key to winterizing is to store your mower properly:

  • If space allows, store mower in a shed or garage to protect from snow, rain and ice storms.
  • An unheated shed or garage is ideal to avoid temperature swings which can cause condensation issues.
  • If storing outside, place away from trees to avoid sap dripping onto mower.
  • Avoid low spots in yard where melting snow could pool and freeze into ice.
  • Raise and lock the mower deck in the highest position so no weight rests on deck shell.
  • For zero turn riders, engage the parking brake and chock the wheels to prevent rolling.

Proper winter storage will keep your mower protected and make spring start-up easy.

FAQs About Winterizing a Lawn Mower

Winterizing your mower will pay dividends when spring arrives, but you may still have some questions about the process. Here we answer some of the most frequently asked questions about lawn mower winterization and storage.

Should I completely drain the fuel or use stabilizer?

The best practice is to completely drain the gasoline from the fuel tank and carburetor before storage. Fuel stabilizer like Sta-Bil is a good option for short storage, but draining prevents potential issues from degraded gas. Run the mower dry after draining to use up residual fuel.

How do I know if my mower needs new oil?

Change the engine oil if it has been more than 50 hours or 3 months since the last oil change. Used oil darkens and thickens over time and can degrade into sludge or varnish, which makes it ineffective at lubricating the engine internals.

Is winterizing just for riders and push mowers?

While larger riding and push mowers need thorough winterizing, smaller electric and battery powered mowers also need proper storage prep. Remove the batteries, wipe the mower clean and keep in a dry indoor location over winter.

Can I leave gas in the mower if I use fuel stabilizer?

While fuel stabilizers like Sta-Bil do slow the degradation of gasoline, it’s still best practice to fully drain the tank and carburetor for winter. Stabilized gas still absorbs moisture over time which can cause trouble restarting.

How do I lubricate joints and cables properly?

Use a lightweight machine oil or lubricant spray like WD-40 when lubricating mower components prior to storage. Soak pivots, cables, axles, and control joints fully but wipe away any drips or excess oil so it is not flung off when mowing resumes.

Is there a fuel additive to help prevent problems?

Yes, fuel stabilizer products like Sta-Bil or SeaFoam contain chemicals that inhibit fuel degradation during storage. Add the correct amount to your tank when full and run the mower to circulate before draining for winter. This protects any residual fuel left after draining.

Should I disconnect the spark plug before storing?

While some recommend removing the spark plug for winter, this is no longer best practice. Removal lets moisture into the cylinder which can cause internal rusting. Cleaning and replacing the plug is sufficient prep. Store the mower with the plugs connected.

How should I clean the mower deck properly?

Use a putty knife or brush to scrape off caked on grass and debris from the deck shell, discharge chute and blade housings. Then wipe down with a degreasing cleaner, rinse and let dry fully. Apply a protectant spray on metal deck parts to deter rust over winter.

Where should I store my mower for winter?

If possible, store your mower over winter in a clean and dry garage or shed protected from the elements. Drain the fuel and let the engine cool before storing. If you must store outside, use a good cover and keep away from rain gutters which may drip water onto the mower.

Should I replace the fuel filter when winterizing?

Replacing the fuel filter is not critical for winterizing but is good periodic maintenance if the filter is more than 1-2 years old. Use the spring startup to replace the filter when you change the oil. Check for debris or water in the old filter when you remove it.


Winterizing protects your mower from damage and prepares it for quick, reliable starting when mowing season returns. Proper storage keeps critical components like the engine, carburetor, and battery functioning for years of continued service.

While the process takes an afternoon, winterizing will save you time and money compared to repairs needed on neglected equipment. Your mower will reward you with worry-free operation next year.

Follow the steps outlined here to fully winterize any gas or electric walk behind mower or riding lawn tractor. Drain the old fuel, change the fluids, sharpen blades and protect metal parts. Store properly over the winter months and your mower will be ready to mow again next spring.