7 Supplies for Winterizing Gas-Powered Garden Equipment

The last cut of the season is done, the air has a distinct chill, and the familiar smell of autumn leaves is everywhere. Before you roll your lawn mower, tiller, or string trimmer into the shed for a long winter’s nap, there’s one final, crucial task. Properly winterizing your gas-powered equipment is the single most important thing you can do to guarantee an easy, trouble-free start next spring.

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Why You Must Winterize Your Garden Equipment

Ignoring your small engines before storage is a recipe for frustration and expensive repairs. Modern gasoline, especially ethanol-blended fuel, can begin to break down in as little as 30 days. As it degrades, it leaves behind a gummy varnish that clogs carburetors, fuel lines, and injectors, leading to hard starts, rough running, or a complete failure to start in the spring.

Beyond fuel issues, the off-season is when moisture and leftover contaminants do their dirty work. Acidic byproducts in used engine oil can etch metal surfaces and bearings, promoting internal corrosion. Dirt, grass clippings, and moisture trapped against the mower deck or engine cooling fins will accelerate rust, compromising the integrity of your equipment over time.

A proper winterizing routine isn’t just about preventing damage; it’s a strategic investment of an hour or two in the fall to save yourself a weekend of headaches and a trip to the repair shop in the spring. It’s the final act of stewardship for the tools that work hard for you all season long. Taking these steps ensures your machines are not just stored, but preserved.

Gather Your Supplies Before You Begin Work

The key to an efficient winterizing session is having everything you need within arm’s reach before you start. There’s nothing worse than getting halfway through an oil change only to realize you don’t have a filter wrench or a proper container for the old oil. A disorganized start often leads to a rushed, incomplete job.

Lay out your supplies on a workbench or a clean patch of concrete. This includes your new oil, fuel stabilizer, cleaning agents, and necessary tools like sockets and wrenches. Don’t forget the less obvious items: shop rags for cleanup, nitrile gloves to keep your hands clean, a drain pan for old oil, and a wire brush for cleaning spark plugs and battery terminals.

Think of this as setting up your workstation for a small, important project. By organizing first, you create a logical workflow from cleaning the machine to the final lubrication. This preparation turns a potentially messy chore into a streamlined, satisfying process that you can complete efficiently, knowing every step has been done right.

Fuel Stabilizer – STA-BIL Storage Fuel Stabilizer

The most critical step in winterizing any gas engine is addressing the fuel left in the tank. A fuel stabilizer is a chemical additive that prevents gasoline from oxidizing and degrading during long-term storage. It keeps the fuel fresh and stops the formation of gum and varnish that will inevitably clog your carburetor’s tiny passages.

STA-BIL Storage is the go-to choice because it’s effective, widely available, and has a proven track record. It works by bonding with gasoline to create a protective layer that resists evaporation and chemical breakdown for up to 24 months. Its formulation also includes a water remover to combat condensation that can form in the tank, preventing rust and phase separation in ethanol-blended fuels.

Before using, read the directions carefully to get the mix ratio right—typically one ounce per 2.5 gallons of gas. The best practice is to add STA-BIL to your gas can before filling it up, ensuring a thorough mix, and then use that treated fuel to top off your equipment’s tank. Run the engine for 5-10 minutes to circulate the stabilized fuel through the entire system, from the fuel line to the carburetor, ensuring complete protection. This product is essential for anyone storing gas-powered equipment for more than a month.

Engine Oil – Briggs & Stratton SAE 30 Small Engine Oil

Changing the engine oil before storage is non-negotiable. Used oil is filled with combustion byproducts, moisture, and microscopic metal particles. Leaving this contaminated oil in the crankcase all winter allows these acidic compounds to slowly corrode internal engine components like bearings and cylinder walls.

Briggs & Stratton SAE 30 Small Engine Oil is specifically formulated for the harsh conditions of air-cooled, 4-stroke engines found in most mowers, tillers, and generators. Unlike automotive oil, it contains detergents and additives designed to handle higher operating temperatures and the specific wear patterns of small engines. Using the manufacturer’s recommended oil ensures proper lubrication and protection.

Always check your owner’s manual to confirm the correct oil weight, as some engines may require a multi-viscosity oil like 10W-30. SAE 30 is the standard for most equipment used in warmer weather. This oil is perfect for the hobby farmer who relies on common, workhorse engines from brands like Briggs & Stratton, Honda, or Kohler. It’s not for 2-stroke engines that require an oil-gas mix.

Oil Extractor Pump – Koehler Manual Fluid Extractor

Getting old oil out of a small engine can be a messy affair, especially on lawn mowers where the drain plug is often in an awkward, hard-to-reach spot. An oil extractor pump uses suction to pull the old oil out through the dipstick tube, eliminating the need to tip the machine on its side and risk spilling oil and gas everywhere.

The Koehler Manual Fluid Extractor is a great pick for its simplicity and effectiveness. It’s a hand-operated pump, so you don’t need an air compressor or electricity. With a 6.5-liter capacity, it’s more than large enough for any piece of garden equipment. The unit is self-contained, making the transfer of old oil to a disposal container clean and easy.

For the extractor to work best, you must run the engine for a few minutes to warm the oil. Warm oil is less viscous and flows much more easily. This tool is a game-changer for anyone who dreads the mess of a traditional oil change. It’s not a necessity, but for the small price, it transforms one of the dirtiest maintenance jobs into a quick, clean task.

Spark Plug Socket – Craftsman 5/8-in Spark Plug Socket

The spark plug is the heart of your engine’s ignition system, and it’s a key checkpoint during winterization. Removing it allows you to inspect its condition, clean off any carbon deposits, and, most importantly, fog the engine cylinder with oil for rust prevention. A dedicated spark plug socket is required for this.

This Craftsman 5/8-inch socket is a reliable choice because it includes a crucial feature: an internal rubber gasket. This gasket gently grips the porcelain insulator of the spark plug, preventing it from cracking during removal and installation and holding it securely in the socket. It’s a small detail that makes a huge difference compared to using a standard deep well socket.

Before buying, you must verify the correct spark plug size for your engine. While 5/8-inch and 13/16-inch are the most common sizes, they are not universal. Check your manual or the plug itself. This tool, paired with a standard socket wrench and extension, is a fundamental part of any small engine maintenance kit.

All-Purpose Degreaser – Simple Green Pro HD Cleaner

A clean machine is a healthy machine. Caked-on grass, dirt, and oil create a perfect environment for moisture to hide, leading to rust and corrosion over the winter. A powerful degreaser is needed to cut through the grime on the engine, frame, and especially the underside of the mower deck.

Simple Green Pro HD is an excellent choice because it’s a heavy-duty cleaner that is safe for sensitive materials. Unlike some caustic degreasers, this professional-grade formula is non-corrosive and safe to use on aluminum, plastics, and painted surfaces found on your equipment. It’s also biodegradable, making it a more responsible choice for cleaning outdoors.

For best results, spray the cleaner on a cool engine and let it sit for a few minutes to penetrate the grime before scrubbing with a stiff brush and rinsing with a hose. Its concentrated formula can be diluted for lighter cleaning tasks, making it a versatile addition to your workshop. This is for the person who understands that cleaning is a critical maintenance step, not just a cosmetic one.

Multi-Purpose Lubricant – WD-40 with Smart Straw

Once your equipment is clean and dry, the final protective step is to lubricate moving parts and shield bare metal from rust. A moisture-displacing lubricant is perfect for protecting throttle cables, linkages, pivot points, and any exposed metal surfaces from the damp winter air.

The classic WD-40 with the attached Smart Straw is ideal for this job. The "Water Displacement, 40th formula" excels at driving moisture out of tight spaces. The genius of the Smart Straw is its dual function: flip it up for a precise stream to hit specific pivot points or cables, and flip it down for a wide spray to quickly coat larger areas like a mower deck.

It’s important to understand what this product is for. WD-40 is a fantastic rust preventative and moisture displacer for storage, but it is not a long-term, high-pressure lubricant for things like wheel bearings. Use it to protect surfaces and free up sticky mechanisms before storage. It’s an indispensable final touch for a thorough winterizing job.

Battery Maintainer – Battery Tender Junior 12V Charger

For any equipment with an electric start, such as a riding mower or a larger generator, the battery needs attention. A lead-acid battery will slowly self-discharge over time, and if left unattended all winter, it can lose its charge completely, sustain permanent damage, and refuse to charge in the spring. A battery maintainer prevents this.

The Battery Tender Junior is a smart choice because it’s more than a simple trickle charger. It’s a fully automatic "smart" maintainer that delivers a full charge and then switches to a float mode. In this mode, it monitors the battery’s voltage and sends a small amount of current only when needed to keep it at an optimal level, preventing the damage caused by overcharging.

This device is designed for long-term, maintenance-free connection. Simply hook it up to your battery (either in the machine or removed and stored separately) and plug it in. It’s a set-it-and-forget-it solution. This is an essential purchase for anyone with a battery-equipped machine; it pays for itself by saving you from buying a new $50-$100 battery every spring.

A Step-by-Step Guide to the Winterizing Process

With your supplies gathered, follow a logical order of operations to ensure nothing is missed. This workflow moves from dirty to clean and from fuel systems to final protection, making the process efficient and thorough. A good plan prevents you from having to redo steps or work on a dirty engine.

Start by cleaning the entire machine. Use your degreaser and a stiff brush to remove all caked-on grass, dirt, and oil. Pay special attention to the mower deck and the engine’s cooling fins. A clean machine is easier to inspect and work on. Next, add the fuel stabilizer to a nearly full tank of fresh gasoline and run the engine for 5-10 minutes. This not only warms the oil for the next step but also circulates the stabilized fuel through the carburetor and fuel lines.

While the engine is still warm, turn it off and change the oil using your extractor pump or the drain plug. After that, disconnect the spark plug wire and remove the spark plug. Inspect it, clean or replace it as needed, and spray a small amount of fogging oil into the cylinder before loosely reinstalling the plug. If you have a battery, connect it to the battery maintainer. Finally, lubricate all moving parts and cables with WD-40 and give any bare metal a light protective coat.

Cleaning and Inspecting Your Equipment Thoroughly

The cleaning phase of winterization is more than just about appearances; it’s a critical diagnostic opportunity. As you scrub away the season’s grime, you get an up-close look at the state of your machine. This is your chance to spot problems that could become major failures next year.

While cleaning the mower deck, check the blades for dullness, chips, or cracks. A sharp blade is key to a healthy lawn, and fall is the perfect time to remove them for sharpening or replacement. Inspect all belts for cracking and wear, and check tire pressure. Look for any loose nuts or bolts and tighten them.

On the engine itself, clearing debris from the cooling fins is vital. Air-cooled engines rely on airflow to prevent overheating, and packed-in grass clippings can lead to serious damage. This thorough inspection turns a simple cleaning chore into proactive maintenance, ensuring your equipment is not only protected for the winter but also ready for peak performance in the spring.

Choosing the Right Spot for Off-Season Storage

Where you store your equipment is just as important as how you prepare it. The ideal storage location protects your machinery from the three biggest enemies of longevity: moisture, temperature extremes, and pests. Leaving a machine outside under a tarp is simply not enough to prevent degradation over a long, wet winter.

A dry garage, a well-built shed, or a barn is the best choice. These structures keep rain and snow off the machine, but more importantly, they reduce the constant exposure to damp air and condensation that promotes rust and corrosion. A stable, moderate temperature is better than a location with wild temperature swings, which can also encourage condensation to form inside the fuel tank and crankcase.

Finally, consider pests. Mice and other rodents love to build nests in the cozy confines of an engine compartment or air filter housing, chewing through wires and plastic components in the process. Storing your equipment in a secure, rodent-proof structure is the best defense. If that’s not possible, placing mothballs or peppermint oil-soaked cotton balls around the engine can help deter them.

An afternoon spent winterizing your equipment is a direct investment in a smoother, more productive spring. By following these steps and using the right supplies, you’re not just putting your tools away; you’re preserving their function and extending their life. When the grass starts growing again, you’ll be rewarded with an engine that starts on the first or second pull, ready to get back to work.