Learning how to winterize a lawn mower is an essential fall task for any homeowner. Preparing your mower for cold storage involves several key steps to protect the engine and fuel system. If you skip this process, you might face a frustrating and costly repair come spring. This guide will walk you through a simple, effective routine to ensure your mower starts easily when the grass begins to grow again.
How To Winterize A Lawn Mower
The core process of winterizing focuses on preventing two main problems: fuel degradation and engine corrosion. Old gas left in the tank and carburetor can turn into a gummy varnish that clogs critical components. Meanwhile, moisture can lead to rust inside the cylinder and on the mower deck. By following the steps outlined below, you’ll safeguard your investment and extend the life of your machine significantly.
Gather Your Supplies And Safety Gear
Before you begin, collect all necessary materials. Having everything on hand makes the job quicker and more efficient. You will also want to prioritize safety to prevent accidents.
Essential supplies include:
- Fresh fuel stabilizer
- A siphon pump or turkey baster (for gas removal)
- An approved fuel container
- New engine oil and a drain pan
- A new air filter and spark plug
- Socket set, wrenches, and a screwdriver
- Stiff brush and a putty knife
- Garden hose (if you have a water source)
For safety, always work in a well-ventilated area, disconnect the spark plug wire before any maintenance, and allow the engine to cool completely. Wearing safety glasses and gloves is also a smart precation.
Step One: Clean The Mower Deck Thoroughly
Start with a clean machine. Grass clippings, mud, and debris hold moisture and promote rust. A thorough cleaning now prevents corrosion over the winter months.
- Disconnect the spark plug wire to ensure the mower cannot accidentally start.
- Tip the mower on its side, with the air filter and carburetor facing upward to prevent oil from leaking into them.
- Use a putty knife or stiff brush to scrape away caked-on grass from under the deck.
- Rinse the deck with a hose, but avoid direct sprays on the engine, muffler, or air filter.
- Let the mower deck dry completely before moving to the next steps.
Step Two: Address The Fuel System
This is the most critical part of winterization. Modern ethanol-blended gasoline can separate and leave damaging residues in as little as 30 days.
Option A: Stabilize The Fuel
If your mower has less than half a tank of gas, this is the preferred method. It keeps the system sealed and prevents moisture buildup.
- Add a high-quality fuel stabilizer to the gas tank. Follow the bottle’s instructions for the correct ratio.
- Run the engine for 5-10 minutes to circulate the treated fuel throughout the entire carburetor and fuel lines.
- Turn off the engine and let it cool. The stabilized fuel can now sit in the tank all winter.
Option B: Drain The Fuel System
For mowers with a nearly full tank or if you prefer to start with fresh gas in spring, draining is a good alternative.
- Use a siphon pump to remove all gasoline from the fuel tank into an approved container.
- Restart the engine and let it run until it stalls from fuel starvation. This burns the remaining gas in the carburetor float bowl.
- Once the engine stops, you can also consult your manual to see if your carburetor has a drain screw to remove the last few drops.
Step Three: Change The Engine Oil
Old oil contains contaminants and acids that can corrode engine internals during storage. Always change the oil while the engine is warm from the previous step, as warm oil drains more completely.
- Place your drain pan under the mower’s oil drain plug or under the fill tube if your model requires tipping.
- Remove the drain plug or dipstick and allow all the old oil to drain out.
- Replace the drain plug securely.
- Refill the crankcase with the type and amount of oil specified in your owner’s manual. Do not overfill.
Step Four: Replace The Air Filter And Spark Plug
These are inexpensive parts that have a big impact on performance. Replacing them now means your mower is ready to go in spring.
For the air filter:
- Remove the filter cover and take out the old filter.
- If it’s a paper filter, replace it with a new one. If it’s a foam filter, you can wash it in soapy water, let it dry, and apply a light coat of new filter oil.
- Reinstall the filter and cover securely.
For the spark plug:
- Disconnect the spark plug wire.
- Use a spark plug socket to carefully remove the old plug.
- Check the gap on the new plug against your manual’s specification and adjust if needed.
- Thread the new plug in by hand to avoid cross-threading, then tighten it with the socket.
- Reconnect the spark plug wire firmly.
Step Five: Perform Final Lubrication And Inspection
A few last touches will keep moving parts free and identify any issues before storage.
- Lubricate all moving parts, such as the throttle and blade control cables, and the wheel bearings if they have grease fittings.
- Sharpen the mower blade. A sharp blade cuts grass cleanly, promoting a healthier lawn next year. You can use a file or take it to a shop.
- Inspect the mower for any loose bolts, cracks, or worn parts. Tighten or note anything that needs replacement.
- Wipe down the entire mower, especially any metal surfaces, with a lightly oiled rag to give a thin protective coating against rust.
Choosing The Right Storage Location
Where you store your mower is just as important as how you prepare it. The ideal location is clean, dry, and protected from temperature extremes.
A garage or shed is perfect. Avoid leaving the mower outside under a tarp, as trapped moisture can still cause problems. If you must use a tarp, ensure the mower is in a well-ventilated area first. Make sure the storage spot is out of reach of children and pets.
Spring Startup Checklist
When you’re ready to mow again, a quick pre-start check will ensure everything works smoothly. You’ll be glad you took the time to winterize properly.
- Reconnect the spark plug wire if it was disconnected.
- If you drained the fuel, fill the tank with fresh gasoline.
- Check the oil level and top up if necessary.
- Inspect the air filter and clean or replace it if it got dirty over winter.
- Give the mower a quick visual check for any nests or debris from pests.
- Start the engine in an open area and let it run for a few minutes before mowing.
Frequently Asked Questions
What Happens If You Don’t Winterize Your Lawn Mower?
If you don’t winterize your mower, the old gasoline will likely turn into a thick gel that clogs the carburetor jets and fuel lines. This is the most common reason a mower won’t start in spring. You may also face a dead battery, a rusty cylinder, or a seized engine from corroded internal parts.
Can I Just Run The Mower Until It’s Out Of Gas For Winter?
Running the mower until it stalls is a partial step, but it’s not complete winterization. This method only empties the carburetor’s float bowl. Gasoline remains in the fuel tank and fuel lines, where it can still degrade and cause issues. For best protection, you must either add stabilizer to a full tank or physically remove all fuel.
Is It Better To Store A Lawn Mower With Or Without Gas?
For most homeowners, storing the mower with a full tank of stabilized gas is the best practice. A full tank leaves less air space, which reduces condensation and moisture buildup inside the tank that leads to rust. The stabilizer prevents the fuel from breaking down for many months.
How Long Does It Take To Winterize A Lawn Mower?
The entire winterization process typically takes about 30 to 60 minutes for a push mower. Riding mowers may take a bit longer due to their larger size and sometimes more complex oil drainage systems. The time invested is minimal compared to the cost and hassle of a repair next season.
Following this guide on how to winterize a lawn mower is a straightforward project that pays off greatly. By dedicating a short amount of time this fall, you protect your equipment, save money on repairs, and guarantee a quick, reliable start when the first warm days of spring arrive. Your future self will thank you for taking these preventative measures now.