How to Winterize Your Lawn Mower and Power Equipment in Canada

Most spring no-start problems begin in the fall. A mower, trimmer, leaf blower or pressure washer that gets pushed into the corner of the garage with old fuel in the carburetor and water in the pump can spend five months in freezing temperatures slowly turning that small mistake into a repair bill. The fix takes an afternoon. Below is a practical routine for Canadian winters, built from manufacturer guidance and Canadian fire-safety advice. Your operator's manual always has the final word, because engines and pumps differ from model to model.

Before you start

Do your last mow of the season first. If you are also seeding or feeding the lawn this fall, our guide to fall overseeding and winterizing your lawn covers the timing. Then set yourself up safely:

• Work outdoors or in an open garage, away from pilot lights, furnaces and water heaters.
• Let a hot engine cool before you add or drain fuel. Windsor Fire & Rescue Services warns never to refuel lawnmowers, trimmers or other equipment while they are still hot.
• Pull the spark plug wire off the plug before you touch the blade or tip the machine, so the engine cannot start by accident.
• Wear gloves when handling blades.

Gas lawn mowers: fuel, oil, spark plug and blade

Fuel: stabilize it or run it dry

Gasoline goes stale. STIHL Canada notes that fuel can deteriorate in as little as 60 days, leaving varnish in the fuel system. Manufacturers give two different answers, so check which one your manual uses:

• Stabilize and fill. Briggs & Stratton recommends adding fuel stabilizer to fresh fuel in the can according to the package directions, filling the tank, and running the engine for a few minutes so treated fuel reaches the carburetor.
• Drain and run dry. Some manufacturers, especially for handheld two-stroke tools, prefer the tank emptied and the engine run until it stops.

We carry a small selection of fuel stabilizers, and many are also sold at local hardware stores.

Oil and air filter

Change the oil while the engine is still slightly warm so it drains fully, and refill with the grade your manual specifies. Old oil holds acids and debris that you don't want sitting against engine parts all winter. Inspect the air filter at the same time and clean or replace it. A mower tune-up kit usually bundles the filter, spark plug and other service parts for a specific engine, and we also stock small engine oil.

Spark plug

Remove the plug and look at the tip. If it is heavily fouled, cracked or worn, replace it with the part number listed in your manual. Doing it now means the mower is ready on the first warm weekend.

Blade and deck

With the plug wire off, tip a walk-behind mower so the air filter and carburetor face up, which keeps oil and fuel from running where they shouldn't. Scrape packed grass off the underside of the deck, since wet clippings trap moisture and speed up rust. Check the blade for nicks, bends and cracks. A bent blade should be replaced, not straightened. A dull but sound blade can be sharpened over the winter with a blade sharpener, or you can swap in a new mower blade matched to your deck size.

Riding mower batteries

If your mower has a battery, disconnect the negative cable first, then the positive, clean the terminals, and store the battery somewhere cool and dry, away from heat sources. A battery maintainer can keep it topped up over a long winter.

String trimmers and gas leaf blowers

For handheld two-stroke tools, STIHL Canada recommends draining the fuel and then running the engine at idle until it stops, to clear what is left in the carburetor. Their seasonal checklist also covers:

• Cleaning debris from the cylinder fins and starter housing so the engine can cool properly next season.
• Cleaning or replacing the air filter. Brush or tap it clean rather than using fuel, solvent or compressed air.
• Cleaning or replacing the spark plug and checking the gap in your manual.
• Checking for loose fasteners and damaged parts.

Now is also a good time to wind fresh line onto your trimmer head so it doesn't dry out and snap in spring. See our trimmer line and spools.

Cordless mowers and tools: battery storage

Lithium-ion batteries don't need fuel treatments, but they do need a sensible place to spend the winter. The main rule is simple: bring batteries into the house. An unheated shed or garage can drop far below freezing during a Canadian cold snap.

• Don't store them fully charged or fully flat. EGO explains that keeping a battery at full charge over a long storage period can reduce its recoverable capacity. Its batteries discharge themselves to about 30% after 30 days without use. Other brands give their own storage level in the manual.
• Keep them dry. Store batteries away from damp floors and away from the charger if the manual says so.
• Charge at room temperature. Chargers often have a temperature window. One Greenworks 60V battery manual, for example, says to charge only between 6 °C and 40 °C. If a battery has been in the cold, let it warm up indoors before charging.

Pressure washers: protect the pump from freezing

A pressure washer pump holds water after every use, and water that freezes inside it can crack the housing or damage seals. Simoniz Canada's winterizing guide recommends this sequence for both gas and electric models:

1. Flush the pump with clean water to rinse out detergent.
2. Disconnect the water supply and run the unit briefly to push out the remaining water, then shut it off (and unplug an electric model).
3. Connect a pressure washer antifreeze or pump-protector canister to the pump inlet and push fluid through until it comes out of the outlet.
4. On gas models, treat the engine fuel with stabilizer as directed by the manufacturer.

Drain the high-pressure hose, wand and gun too. Simoniz recommends storing electric units inside the house or in a heated garage. We carry a small number of pump protectors along with hoses, nozzles and replacement parts in our pressure washer parts collection.

Storing fuel and equipment safely

Winter storage is also fuel storage. Windsor Fire & Rescue Services advises the following:

• Use only a ULC- or CSA-approved gasoline container.
• Fill containers no more than 90 to 95% full so the fuel has room to expand.
• Keep only the minimum amount you need.
• Store gasoline in a secure, well-ventilated place out of children's reach, ideally a detached garage or shed away from pilot lights, electric motors, heaters and other ignition sources.
• Never store gasoline inside your home or in a vehicle.

The same thinking applies to fuelled equipment: keep it out of the basement and away from fuel-burning appliances. Store machines somewhere dry and away from fertilizer, which can corrode metal. A breathable cover keeps dust off a mower parked in a shed.

Winter storage checklist

• Last mow done, spark plug wire disconnected before servicing.
• Fuel stabilized and circulated, or drained and run dry, following your manual.
• Oil changed, air filter cleaned or replaced, spark plug checked.
• Deck scraped, blade inspected, sharpened or replaced.
• Riding mower battery disconnected and stored cool and dry.
• Trimmer and blower cleaned, fuel drained, fresh line on the spool.
• Cordless batteries indoors, partly charged, dry.
• Pressure washer flushed, drained and protected with pump antifreeze; electric units stored indoors.
• Gasoline in an approved container, in a ventilated outbuilding, away from ignition sources.

Once the lawn equipment is put away, it's a good time to cover the patio set and barbecue too. Our guide to winterizing patio furniture and the grill walks through it.

Frequently asked questions

Should I leave gas in my lawn mower over the winter?

It depends on the manufacturer. Briggs & Stratton recommends a full tank of fuel treated with stabilizer, run briefly through the engine, while STIHL recommends draining handheld tools and running them until they stop, so follow your operator's manual.

How long does gasoline last in small engines?

STIHL Canada notes that fuel can start to deteriorate in as little as 60 days, which is why untreated fuel left over a Canadian winter often causes hard starting in spring.

Can I leave cordless mower batteries in the garage?

It's better to store them indoors, in a dry place and above freezing. Many manufacturers also recommend storing lithium-ion batteries partly charged rather than full, and warming a cold battery to room temperature before charging.

How do I stop my pressure washer pump from freezing?

Flush the pump, run it briefly with the water disconnected to purge it, then push pressure washer antifreeze or a pump protector through the pump until it comes out of the outlet. Drain the hose and wand, and store electric units indoors.

Where should I store gasoline over the winter?

Keep it in a ULC- or CSA-approved container filled no more than 90 to 95%, in a ventilated detached garage or shed away from pilot lights and other ignition sources. Never store it in your home or vehicle.