Gas-powered lawn movers take their share of abuse during the warm months, so winterizing at the end of the season can keep them in good condition. “If you don’t take an hour or two for maintenance or bring your machines to a pro for servicing,” says mechanic Audrey Meinking, “there’s a big chance you’ll be stuck watching the grass grow come spring.” By following a few simple steps, you can protect your investment and avoid mower breakdowns when spring comes around.
Empty the Lawn Mower Gas Tank
Gas left in a mower through the winter can turn stale, gumming up the carburetor and causing rust to form. Here’s how to empty the gas tank so you can start fresh in the spring:
- Start by adding one ounce of fuel stabilizer per two gallons of fuel to the gas tank.
- Run the mower to distribute it through the engine.
- Turn off the mower and let the engine cool.
- Siphon the excess gas into a clean can.
- Start the mower again, then run it until it stops to burn any lingering fuel.
If you have a 4-cycle mower where the gas doesn’t mix with the oil, you can usually put the gas you siphoned into your car. Otherwise, store the gas in an approved metal or plastic container within a detached garage or shed, and keep it at least 50 feet away from all ignition sources.
Pro Tip: Craig Murray, owner of Liffco Power Equipment in Mineola, N.Y., advises: “Don’t leave cans of gasoline sitting around, because the fuel will absorb water, which makes motors run rough. Funnel whatever’s left into your car’s tank, then buy fresh gas come springtime.”
Disconnect and Inspect the Mower Spark Plug
If the mower accidentally kick-starts from a connected spark plug, you could get seriously injured. Here’s how to safely disconnect your mower’s spark plug:
- Locate the spark plug—you can typically find these on the side of the engine.
- There should be a thick wire at the end of the spark plug, potentially connected with a spring clip or friction fit. Remove the wire by hand or with a set of pliers.
- Then, carefully turn the plug counterclockwise to loosen it.
Once the spark plug is out, examine it for any damage or debris. If you notice oily residue or black deposits of carbon on the plug, replace it immediately.
Pro Tip: Before removing the blade, pull the spark plug wire to prevent an accidental start-up. When unbolting the blade, wedge a scrap of 2×4 against it so it won’t turn, and mark the blade’s face with an X to ensure correct reinstallation. If sharpening by hand, clamp the blade in a vise and make long passes along the beveled cutting edge with a 12-inch mill bastard file, starting near the center of the blade and feathering off at the tip.
Removing and Sharpening the Lawn Mower Blade
Sharpening your lawn mower blades can offer a cleaner cut, lead to more efficient mowing, and enable less wear and tear on your machine. Before handling any blades, put on thick gloves to protect your hands. Then, unscrew the bolts that hold the blade in place with a socket wrench. Once you’ve removed the blade, sharpen it yourself with a grinder blade or take it to a hardware store and have a professional do it for you.
Pro Tip: This Old House landscape contractor Roger Cook advises: “You let the lawn tell you when to sharpen. You take a piece of grass after you cut it and you look at it. If it’s a nice clean cut on the top of a piece of grass, then your blade is great. If it’s all ragged on the edge, that’s not good.” A ragged cut can invite disease into the grass and leave your lawn with a brown cast a few days after mowing.
Draining the Oil From Your Mower
If you have a 4-cycle mower, drain your oil at least once every spring or summer, or every 50 hours of use.
- Have a pan ready and put a tarp under the mower to catch spatter.
- Set the mower on its side with the air filter and carburetor facing up, so oil and residual gas don’t spill into them.
- Remove the oil reservoir plug and slowly tilt the mower until oil drains into the pan.
- Replace the plug once the tank is empty, and dispose of the old oil at a local recycling center, mechanic, or auto parts store.
Cleaning the Mower Undercarriage
With the blade off and tanks drained, deep-clean your mower deck to prevent rust and keep the pathways to the bag attachments and discharge chutes open. Use a putty knife and wire brush to remove caked-on grass and mud.
Pro Tip: Roger Cook, This Old House landscape contractor, recommends finishing the job with a protective coating: “I’m gonna spray the underside with a lubricant… That’s gonna make it slick so that no grass is gonna stick in there anymore.”
Reattaching the Mower Blade and Refilling the Oil Tank
Once the undercarriage is clean, you can reattach the sharpened blade and fill the oil tank. Use fresh SAE 30 or 30-weight oil instead of thicker oils, such as 10W-40.
Replacing the Lawn Mower Air Filter
A dirty air filter makes your mower less fuel-efficient, so consider replacing it before storing it away for the winter. Some mowers have paper filters, while others have oil-soaked sponge filters. If you have a paper filter, replace it with a new one so the paper edges face out. If you have an oil-soaked filter, remove it, wash it with soap and water, let it dry completely, and add some clean oil to it before you replace it.
After replacing the air filter, clear the cooling fins of dirt and debris with a screwdriver or popsicle stick.
Pro Tip: Remember that sharpening removes metal from the blade. As This Old House landscape contractor Roger Cook explains, you want to make sure you remove the same amount from each side so that the blade stays in balance. “If it’s out of balance, it can cause damage to the machine,” he warns, since the blade spins at high speed off the center axis. You can check the balance with an inexpensive plastic balancer available at most hardware stores.
Installing a New Spark Plug in Your Mower
Even if your old spark plug is in good shape, a new one will perform better for only a few extra dollars. You can purchase a new spark plug from your local auto or home improvement store. Use a socket wrench with a spark plug socket to install the new plug, then put the cover back in place.
Our Conclusion
Getting your lawn mower ready for the winter season can ensure it’s ready in the spring and extend the lifespan of the machine. You can complete the above winterization steps on your own, but if you need assistance repairing mower, contact a lawn mower repair specialist to assist.
