Last Updated on February 21, 2026 by D. Ruddy
Getting your gas lawn mower ready for winter might sound like a chore, but it’s really important to keep it running smoothly for next spring. Many people find How to winterize a gas lawn mower step by step a bit tricky at first. You might worry about messing something up or not doing it right.
Don’t worry! This guide will make it super simple, with easy steps to follow. We’ll cover everything you need to know to protect your mower.
Let’s get started on making sure your mower is happy and healthy all winter long.
Key Takeaways
- You will learn the essential steps for preparing your gas lawn mower for winter storage.
- This guide will explain how to properly drain or treat the fuel system to prevent damage.
- You will discover the importance of cleaning your mower and changing the oil.
- Learn how to prepare the battery for winter to ensure it works next season.
- Understand how to protect the mower’s blades and other metal parts from rust.
- This post will help you store your mower safely and effectively for the cold months.
Preparing Your Gas Lawn Mower for Winter Storage
Getting your gas lawn mower ready for winter is a key part of keeping it in good shape. If you just leave it out in the cold and damp, it can cause problems when spring rolls around. Things like rust can form, and the fuel can go bad, making it hard to start.
This section will walk you through the first few important things you need to do. We’ll focus on cleaning and getting the fuel ready. Doing these simple steps now saves you a lot of headaches later.
Cleaning Your Lawn Mower
A clean mower is a happy mower, especially when it’s heading into storage. You’ll want to get off all the grass clippings, dirt, and mud that have built up over the mowing season. This prevents them from hardening or attracting moisture, which can lead to rust or even damage to the engine components.
A good cleaning also lets you spot any other issues, like loose parts or damage, before they become bigger problems.
Start by disconnecting the spark plug wire. This is a very important safety step to make sure the engine doesn’t accidentally start while you’re working on it. Next, use a brush or a leaf blower to remove loose debris from the deck, engine, and wheels.
For tougher grime, a wet rag or a gentle hose spray can work. Make sure to avoid spraying water directly into the engine. After washing, dry everything thoroughly to prevent rust.
Why Cleaning is Important
Leaving grass clippings and dirt on your mower can trap moisture. This moisture can then cause metal parts to rust over time. Rust weakens the metal and can eventually make parts break or wear out faster.
Grass and debris can also clog up moving parts, like the blade mechanism or cooling fins on the engine. This can make the mower work harder and overheat. By cleaning it well, you protect the mower’s body and its engine.
It also makes it easier to see any minor damage, like a loose bolt or a crack, that you might otherwise miss.
Tools for Cleaning
You don’t need fancy tools to clean your mower. A stiff brush is great for scraping off caked-on mud and grass. A putty knife or a scraper can help with really stubborn bits, but use it gently so you don’t scratch the paint.
A shop vacuum can be useful for sucking out dry leaves and debris from hard-to-reach spots. For a more thorough wash, a hose with a spray nozzle is fine. Just remember to aim away from the engine and electrical parts.
Some people like to use a degreaser for really oily spots, but make sure it’s safe for your mower’s materials.
Dealing with the Fuel System
The fuel in your lawn mower is probably the most critical thing to address when winterizing. Gasoline doesn’t stay good forever. Over time, it can break down, leaving behind sticky deposits.
These deposits can clog up the carburetor and fuel lines, making it very difficult or impossible to start your mower next spring. You have two main options for handling the fuel: either drain it completely or add a fuel stabilizer.
Option 1: Draining the Fuel
Draining the fuel completely is a sure way to prevent fuel-related problems. This method is especially good if you won’t be using the mower for many months or if you have old gasoline. You’ll need a safe container to collect the fuel.
Make sure you are in a well-ventilated area, away from any open flames or sparks. Disconnect the spark plug wire first, as always. Then, you can tilt the mower to pour the fuel out of the tank into your container, or use a siphon pump to draw the fuel out.
Once the tank is empty, start the engine and let it run for a few minutes until it stops on its own. This will burn off any remaining fuel in the carburetor.
Option 2: Adding Fuel Stabilizer
If draining the fuel seems like too much work, adding a fuel stabilizer is a great alternative. A fuel stabilizer is a chemical additive that prevents gasoline from breaking down and oxidizing. It keeps the fuel fresh for a long time, often up to a year.
To use it, you’ll first add the correct amount of stabilizer to your gas tank while there’s still fuel in it. Then, you’ll run the engine for about 5-10 minutes. This allows the stabilized fuel to circulate through the entire fuel system, including the carburetor.
This ensures all parts are protected. Make sure to buy a stabilizer that is specifically made for small engines and follow the product’s instructions carefully.
Why Fuel Stabilization Matters
Gasoline is made up of many different components. Some of these components are more volatile and will evaporate or degrade faster than others. When this happens, the gasoline can lose its octane rating and become less effective.
It can also start to form gummy deposits. These deposits are like sticky glue that can clog small fuel lines and jets in the carburetor. Over the winter, even a small amount of fuel left in the tank can go bad.
Using a stabilizer prevents this breakdown. It binds with the fuel molecules, creating a more stable mixture that won’t degrade as easily. This keeps the fuel fresh and the engine components clean and ready for use.
Engine Maintenance for Winter Storage
Beyond cleaning and fuel, taking care of the engine itself is vital for winter storage. This includes changing the oil and checking the spark plug. These steps ensure that the engine’s internal parts are protected from wear and corrosion while it sits idle.
A little effort now can save you from costly repairs and a frustrating spring startup. Let’s look at how to do these tasks simply and effectively.
Changing the Engine Oil
The oil in your lawn mower engine collects dirt, metal shavings, and moisture throughout the mowing season. If you leave old, dirty oil in the engine over the winter, these contaminants can cause corrosion and wear on internal parts. Fresh oil is clean and contains additives that protect against rust and wear.
Changing the oil before storing the mower is like giving your engine a protective bath.
To change the oil, you’ll need a few things: new engine oil (check your mower’s manual for the correct type and amount), a wrench to remove the oil drain plug, a drain pan, and a funnel. First, run the engine for a few minutes to warm the oil. Warm oil flows better and carries more contaminants out with it.
Park the mower on a level surface and disconnect the spark plug wire. Locate the oil drain plug, usually at the bottom of the engine. Place your drain pan underneath it and carefully remove the plug with a wrench.
Let all the old oil drain out. Once it’s empty,
Benefits of Fresh Oil
Fresh engine oil does more than just lubricate. It contains important additives that help keep the engine clean and protected. These additives include detergents that help prevent sludge buildup, dispersants that keep particles suspended so they can be drained out, and anti-wear agents that reduce friction.
Crucially for winter storage, fresh oil also contains rust inhibitors. When the mower sits, condensation can form inside the engine. These inhibitors help prevent that moisture from causing rust on metal surfaces.
Old oil loses these protective qualities over time, making the engine more vulnerable to damage during the off-season.
When to Change Oil
Ideally, you should change your lawn mower’s oil at least once a year. The best time to do this is at the end of the mowing season, just before you store it for the winter. This way, the engine has fresh, protective oil in it throughout the storage period.
If you use your mower very frequently or in harsh conditions, you might need to change it more often, as recommended in your owner’s manual. Some manuals suggest changing it after every 25-50 hours of use, or at the end of each season. Following the manual’s advice is always the safest bet.
Inspecting and Servicing the Spark Plug
The spark plug is what ignites the fuel in your engine, so it needs to be in good working order. Over time, the spark plug can get dirty or worn, leading to starting problems. For winter storage, it’s a good idea to check its condition and perhaps even replace it.
This ensures a strong spark when you need to start your mower next spring.
To check the spark plug, first make sure the spark plug wire is disconnected. Then, use a spark plug wrench to carefully unscrew the spark plug from the engine. Inspect the tip of the spark plug.
If it looks black, oily, or heavily worn, it’s probably time to replace it. You can buy a new spark plug at most hardware or auto parts stores. Make sure to get the correct type for your mower’s make and model.
When installing a new spark plug, thread it in by hand first to avoid cross-threading. Then, use the wrench to tighten it snugly. Don’t overtighten it.
Reconnect the spark plug wire firmly.
What a Spark Plug Does
The spark plug’s job is to create a spark that ignites the air-fuel mixture inside the engine cylinder. It has a central electrode and a ground electrode, with a gap between them. When the ignition system sends a high-voltage pulse to the spark plug, a strong electrical arc jumps across this gap.
This arc ignites the compressed fuel and air. If the spark plug is dirty, fouled with oil, or has too much gap, the spark might be weak or not occur at all. This can lead to the engine misfiring, running rough, or not starting.
A clean, properly gapped spark plug ensures a strong spark for efficient combustion.
When to Replace a Spark Plug
It’s a good practice to
Protecting Your Mower’s Components
Once the main engine and fuel are handled, we need to think about other parts of the mower that can suffer from sitting for months. This includes the blades, the battery (if your mower has one), and any exposed metal surfaces. Taking steps to protect these parts will prevent damage and ensure everything is ready to go when you are.
Blade Care and Protection
The mower blade is constantly exposed to grass, dirt, and moisture. Over the winter, if left dirty and damp, it can start to rust. A rusty blade isn’t just unsightly; it can also be less effective at cutting grass, potentially tearing it instead of slicing it cleanly.
This can stress your lawn. Taking a moment to clean and protect the blade is a small effort that pays off.
First, disconnect the spark plug wire for safety. Then, carefully tip the mower onto its side, ensuring the carburetor is facing upwards to prevent fuel or oil leaks. Use a stiff brush or a rag to clean the blade thoroughly, removing all grass and dirt.
You can also use a wire brush for tougher grime. Once clean, you should lubricate the blade. Apply a light coating of oil or grease to the blade surfaces.
This creates a barrier that helps prevent rust from forming. You can use motor oil, WD-40, or a spray lubricant for this. After lubricating, give the blade a gentle wipe to remove excess.
This simple step will keep your blade sharp and rust-free.
Why Blade Maintenance is Key
A sharp, well-maintained blade cuts grass cleanly. This leads to a healthier lawn. When a blade tears grass, it leaves ragged edges that are more prone to disease and can make the lawn look unhealthy.
A clean blade also helps prevent the spread of diseases between different areas of your lawn or from your mower to other lawns. For winter storage, preventing rust is the primary concern. Rust can weaken the blade and make it dull.
Lubricating the blade creates a protective shield against the elements, ensuring it remains in good condition until the next mowing season.
Sharpening vs. Lubricating
While lubricating the blade prevents rust, it doesn’t sharpen it. Sharpening is a separate process that should ideally be done before storage or at the start of the mowing season. If your blade is dull, you can sharpen it yourself using a file or a grinding wheel, or take it to a professional service.
After sharpening, always clean and lubricate it. For winterizing, if your blade is already sharp, a good cleaning and a coat of oil are sufficient. If it’s dull, sharpening it first, then cleaning and lubricating, is the best approach to ensure peak performance next spring.
Battery Care (for Electric Start Mowers)
If your lawn mower has an electric start, it has a battery. Like any battery, if left discharged for long periods, especially in cold temperatures, it can lose its charge and its ability to hold a charge. Proper battery care is essential to ensure your mower starts easily next season.
The best way to care for a mower battery over winter is to disconnect it from the mower. Clean any corrosion off the battery terminals with a wire brush and a baking soda and water paste. Then, charge the battery fully.
After charging, store it in a cool, dry place, ideally off the concrete floor (which can help discharge batteries). Many people recommend placing it on a wooden shelf or a piece of cardboard. It’s also a good idea to check the charge level periodically over the winter and recharge it if needed.
A battery tender or trickle charger can help maintain a full charge without overcharging.
Understanding Battery Discharge
Batteries naturally lose charge over time, a process called self-discharge. This happens even when the battery is not connected to anything. The rate of self-discharge can be affected by temperature; warmer temperatures tend to increase it.
When a battery is left discharged for too long, especially in cold weather, the chemical reactions inside can become irreversible, leading to permanent damage. This is why it’s important to keep batteries charged, especially during long storage periods like winter. A fully charged battery is more resistant to this type of damage.
Types of Battery Chargers
There are a few types of chargers you might use. A standard battery charger will bring your battery up to full charge, but you need to disconnect it once it’s charged to avoid overcharging. A battery maintainer, also known as a trickle charger or battery tender, is designed to keep a battery at a full charge over extended periods.
It monitors the battery’s voltage and delivers a low current when needed to keep it topped up. These are ideal for winter storage as they prevent overcharging and damage. Always follow the charger’s instructions and ensure it’s compatible with your mower’s battery type (usually 12-volt lead-acid).
Lubricating Other Metal Parts
Beyond the blade, there are other metal parts on your mower that can benefit from a little lubrication to prevent rust and seizing. Think about pivot points, levers, and any exposed metal that might be exposed to moisture. A light application of oil or grease on these areas will create a protective layer.
After cleaning your mower, identify areas like the throttle control cable, steering components (if applicable), or any other hinges and pivot points. Apply a light spray of lubricant or a dab of grease to these spots. Work any moving parts a few times to ensure the lubricant spreads evenly.
Avoid getting lubricant on the drive belt or friction surfaces where it could cause slipping. A general-purpose lubricant or a silicone-based spray works well for most of these areas. This helps keep them moving freely and prevents rust from forming where parts meet.
Proper Storage of Your Winterized Lawn Mower
You’ve done the hard work of cleaning, fueling, and maintaining your mower. Now, the final piece of the puzzle is how you store it. Where you keep your mower and how it’s positioned can make a big difference in how well it survives the winter.
Proper storage is the last step to ensure a smooth startup next season.
Choosing the Right Storage Location
The best place to store your winterized lawn mower is in a dry, protected environment. A garage, shed, or even a basement is ideal. The key is to keep it away from the elements – rain, snow, ice, and extreme temperature fluctuations.
Outdoor storage, even under a tarp, is generally not recommended for long-term winter storage as it offers less protection from moisture and temperature changes, which can still affect the mower.
If you don’t have a garage or shed, consider investing in a mower cover that is designed for outdoor use. Make sure it’s breathable to prevent moisture buildup underneath. Elevating the mower slightly, perhaps by placing it on wooden blocks, can also help keep it off cold, damp concrete, which can sometimes lead to rust on the tires or metal frame.
The goal is to create a stable, dry environment for your mower to rest.
Why a Dry Location is Important
Moisture is the enemy of metal. Over the winter, condensation can form even in seemingly dry spaces. If your mower is stored in a damp environment, this moisture can slowly corrode metal parts, leading to rust.
A dry location minimizes this risk significantly. It also helps prevent mold and mildew from growing on any fabric parts or the seat. Keeping the mower protected from the elements also shields it from potential damage caused by animals seeking shelter or by falling debris.
A dry, secure spot is the best defense against winter’s harsh effects.
Temperature Considerations
While extreme cold itself isn’t usually the main problem for a gas mower, rapid and drastic temperature swings can be. These swings can cause condensation to form more readily inside the engine and fuel tank. Storing the mower in a location with more stable temperatures, like a climate-controlled garage, is beneficial.
However, for most home garages or sheds, simply keeping it out of direct sunlight and away from extreme wind and rain is usually sufficient. The most important factor is keeping it dry.
Positioning Your Mower for Storage
How you position your mower can also be important for preventing leaks and damage during storage. If your mower has a fuel tank, it’s generally best to store it on a level surface. Some people recommend storing a mower with the fuel tank nearly empty (if you drained it) or full (if you used stabilizer).
A nearly empty tank can reduce the amount of stale fuel that might be present, while a full tank can help prevent moisture from condensing inside. For simplicity and if you drained the fuel, storing it on its side is usually okay as long as the carburetor is facing up. However, many manufacturers suggest storing mowers upright whenever possible.
If you must store the mower on its side, be very careful about which side you choose. Always place it on the side that has the air filter and carburetor pointing upwards. This prevents oil and fuel from leaking into these sensitive areas.
If you have a push mower, storing it upright is usually the easiest and safest option. If your mower has large wheels, storing it upright will take up more space but ensures no fluids are compromised. Consult your owner’s manual for specific advice on your model.
Potential Issues with Incorrect Positioning
Storing a mower incorrectly, especially on its side with the wrong orientation, can lead to several problems. Fuel can leak out of the tank or carburetor, creating a fire hazard and a mess. Oil can also leak into the air filter housing or the carburetor, which will require cleaning before you can start the mower.
If the mower is stored with the spark plug opening facing downwards, oil might seep into the cylinder, causing excessive smoke when it’s started. Storing it on its side for too long can also strain the engine seals. Therefore, paying attention to the correct position is quite important.
Upright vs. Sideways Storage
Storing your mower upright is generally the safest and most recommended method. It minimizes the risk of fuel and oil leaks and keeps these fluids away from the carburetor and air filter. It also puts less stress on seals and gaskets.
However, upright storage can take up more space, especially for larger riding mowers. If you need to store it on its side due to space constraints, always ensure the carburetor and air filter are on the higher side to prevent liquid intrusion. For most walk-behind mowers, upright storage is feasible and preferred.
Frequently Asked Questions
Question: Do I need to drain the gas or can I just use stabilizer?
Answer: You have two good options. You can either drain all the gas out of the tank and run the engine until it stops to clear the carburetor, or you can fill the tank with fresh gas and add a fuel stabilizer. The stabilizer keeps the gas from going bad over the winter.
Question: How often should I change the oil in my lawn mower?
Answer: It’s best to change the oil at least once a year, and the ideal time is at the end of the mowing season before storing it for winter. This ensures the engine has fresh, protective oil throughout the off-season.
Question: What if I don’t have a garage to store my mower?
Answer: If a garage or shed isn’t an option, you can store your mower outdoors with a good quality, breathable mower cover. Try to elevate it off the ground to prevent moisture from the ground affecting it.
Question: Can I just leave the old gas in the tank?
Answer: No, it’s not recommended. Old gas can break down, leave sticky deposits that clog the carburetor, and make your mower hard to start in the spring. You should either drain it or use a fuel stabilizer.
Question: How do I know if my spark plug needs replacing?
Answer: Look at the tip of the spark plug. If it’s black, oily, or looks worn down, it’s time for a new one. Replacing it is a simple step that ensures good performance next season.
Final Thoughts
Winterizing your gas lawn mower is a simple process that protects your investment. By following these steps for fuel, oil, cleaning, and storage, you ensure your mower starts easily next spring. This guide provides everything you need to know.
Get it done now and enjoy a worry-free start to the next mowing season!
