Learning how to winterize a riding lawn mower is an essential task for any homeowner who wants to protect their investment. Preparing your riding mower for cold months involves several key steps to protect its systems. Neglecting this process can lead to costly repairs come spring, from a seized engine to a ruined fuel system. This guide will walk you through the complete procedure in a clear, step-by-step manner.
How To Winterize A Riding Lawn Mower
The core process of winterizing your mower focuses on stabilizing the fuel, protecting the engine, and preventing corrosion. By following this structured approach, you ensure your machine starts easily when the grass begins to grow again. Set aside about an hour of time, gather some basic supplies, and let’s get started.
Gather Your Winterizing Supplies
Before you begin, it’s helpful to have everything you need on hand. This makes the job smoother and ensures you don’t skip a critical step. You likely have many of these items in your garage already.
- Fuel stabilizer
- Fresh engine oil and a new oil filter
- A socket set, wrenches, and a screwdriver
- A fuel siphon pump or a turkey baster dedicated to garage use
- A sturdy jack and jack stands for safely lifting the mower
- Spark plug socket and a new spark plug
- Air filter (or materials to clean a reusable one)
- Grease gun for fittings (if applicable)
- A soft brush and compressed air for cleaning
- A battery tender or trickle charger
Step 1: Clean The Mower Thoroughly
Always start with a clean machine. Grass clippings, mud, and debris hold moisture, which leads to rust and corrosion over the winter. A clean mower also makes it easier to spot any leaks or potential problems.
- Use a brush or a putty knife to scrape off large clumps of dried grass from the mower deck, especially around the spindle housings.
- Hose down the entire mower, but avoid direct, high-pressure sprays on the engine, carburetor, or electrical components.
- Allow the mower to dry completely in the sun or a well-ventilated space before proceeding to the next steps. Storing it wet is a recipe for rust.
Step 2: Address The Fuel System
This is arguably the most critical step. Old gasoline left in the system will break down, forming gummy varnish that clogs the carburetor’s tiny jets and passages. This is the primary reason for hard starting in the spring.
Option A: Stabilize The Existing Fuel
If your gas tank is more than half full, adding a fuel stabilizer is the best course of action. Run the engine to circulate the treated fuel through the entire system.
- Add the correct amount of fuel stabilizer to the gas tank. Follow the instructions on the bottle carefully.
- Start the mower and let it run for 5-10 minutes. This allows the stabilized fuel to reach the carburetor and fuel lines.
- Turn off the engine and proceed with the rest of the winterization steps.
Option B: Drain The Fuel System
For an empty or nearly empty tank, or if you prefer not to keep fuel in the system, draining is a reliable alternative.
- Use a siphon pump to remove all gasoline from the fuel tank into an approved fuel container.
- Restart the engine and let it run until it stalls from fuel starvation. This burns the remaining gas in the carburetor bowl.
- Once the engine is cool, you may also consider disconnecting the fuel line and draining any residual fuel from the carburetor bowl if your model allows for easy access.
Step 3: Change The Engine Oil And Filter
Never store an engine with old, used oil. Contaminants and acids in the old oil can corrode internal engine components over the winter. Always change the oil while the engine is warm from the previous stabilization step, as warm oil drains more completely.
- Locate the oil drain plug underneath the mower. Place a drain pan underneath it.
- Remove the drain plug and the oil fill cap to allow air to flow, letting the oil drain fully.
- Once drained, replace the plug and install a new oil filter if your mower has one.
- Refill the crankcase with the type and amount of oil specified in your owner’s manual. Do not overfill.
Step 4: Remove Or Maintain The Battery
A dead battery is a common springtime surprise. Cold temperatures can kill a battery left connected in an unused machine.
- Best Practice: Remove the battery entirely. Clean the terminals with a baking soda and water solution to neutralize acid, rinse, and dry. Store the battery in a cool, dry place off concrete floor, and connect it to a battery tender or trickle charger monthly.
- Alternative: If you cannot remove the battery, at minimum disconnect the negative (black) cable to prevent parasitic drain. It is still advisable to use a maintainer if possible.
Step 5: Service The Air Filter And Spark Plug
These are simple, inexpensive items that have a big impact on performance. Replacing them now means your mower is ready to go in the spring.
- Air Filter: Remove the air filter cover. If it’s a paper filter, replace it with a new one. If it’s a foam filter, wash it gently in soapy water, rinse, dry thoroughly, and re-oil it if required by the manufacturer.
- Spark Plug: Disconnect the spark plug wire. Use a spark plug socket to remove the old plug. Check the gap on the new plug with a gap tool, then carefully thread it in by hand before tightening with the socket. Reconnect the wire firmly.
Step 6: Lubricate Moving Parts
Protect pivot points and other components from seizing up. This prevents stiffness and wear when you start using the mower again.
- Apply a few drops of oil to the throttle and choke control linkages.
- Grease any zerks fittings you find on the mower deck spindles or steering components.
- Lightly lubricate the clutch and brake pedal pivots.
- Consider spraying a silicone-based protectant on the seat and rubber components to prevent drying and cracking.
Step 7: Prepare The Mower Deck And Blades
This step protects the underside of your mower from rust and keeps the blades sharp for next season.
- With the engine off and the spark plug wire disconnected, carefully inspect the blades for damage and sharpness.
- If the blades are dull or nicked, remove them (marking which side faces the ground for reinstallation) and have them sharpened or replace them.
- Once the deck is clean and dry, consider spraying the underside with a light coating of silicone spray or fluid film to create a barrier against moisture. This can significantly reduce rust formation.
Step 8: Choose The Right Storage Location
Where you store your mower matters. An unheated shed or garage is fine, but certain conditions should be avoided.
- Store the mower in a clean, dry place. Avoid damp, dirt-floor cellars.
- If you must store it on a concrete floor, place a piece of plywood or a mat underneath the tires to prevent dry-rotting.
- Cover the mower with a breathable fabric cover or an old sheet. Avoid plastic tarps, as they trap moisture and promote condensation and rust.
- Make sure the storage area is free from rodents, who might chew on wiring or make nests in the engine compartment.
Final Checklist Before Storage
Run through this quick list to ensure you haven’t missed anything crucial.
- Fuel system stabilized or drained.
- Fresh oil and filter installed.
- Battery removed and on a maintainer or disconnected.
- New spark plug and clean air filter installed.
- Mower cleaned, deck prepared, and blades serviced.
- Moving parts lubricated.
- Mower parked in a dry location and covered appropriately.
Frequently Asked Questions
What Happens If You Don’t Winterize A Riding Lawn Mower?
Failing to winterize can lead to several expensive problems. Gasoline will degrade and clog the carburetor, requiring a rebuild or replacement. Moisture in the oil can cause internal engine corrosion. The battery will likely discharge completely and be ruined. You may face hundreds of dollars in repairs that could of been easily avoided.
Can I Just Run The Mower Out Of Gas For Winter?
Running the engine until it stalls is part of the draining process, but it’s not a complete solution on its own. While it empties the carburetor bowl, fuel remains in the lines and tank where it can still degrade. For best results, combine running the engine dry with either adding stabilizer to a full tank or physically siphoning out all the old fuel.
Is It Better To Store A Lawn Mower With Or Without Gas?
Both methods are acceptable if done correctly. The consensus among small engine mechanics is that storing with a full tank of stabilized fuel is often best. A full tank leaves less air space, which reduces condensation and water buildup inside the tank over the winter. The key is always using a fuel stabilizer.
Should I Change The Oil Before Or After Winter Storage?
Always change the oil before storage. Used oil contains combustion byproducts and acids that are corrosive. Letting that sit in your engine all winter can accelerate wear on bearings and other internal surfaces. Fresh, clean oil provides much better protection during the storage period.
How Long Does It Take To Winterize A Riding Mower?
The entire process typically takes between 60 to 90 minutes for someone familiar with the steps. If it’s your first time, allow up to two hours to work carefully and consult your manual. This small investment of time each fall saves you many hours of frustration and money on repairs when spring arrives.