How to Winterize Your Lawn Mower for the Ottawa Valley Winter
If you live anywhere from Arnprior to Renfrew, Pakenham to Calabogie, you already know the score: the mower gets parked sometime in late October, and by the time the grass is growing again in May it has sat untouched for the better part of five months. How you put it away in the fall decides whether spring starts with a satisfying first-pull roar -- or a frustrating morning of pulling a dead cord and smelling stale, varnished gas.
As an authorized Briggs & Stratton dealer right here in Arnprior, we see the same preventable failures roll through the shop every May. Almost all of them trace back to one thing: the machine was never properly winterized. Here is exactly how to do it right for an Ottawa Valley winter.
Why Winterization Matters in the Ottawa Valley
Our winters are long and genuinely cold. A mower that gets put away in late October often will not run again until May -- that is roughly five months of sitting in an unheated shed or garage while temperatures swing well below freezing for weeks at a stretch. Two things happen during that stretch that wreck small engines.
First, ethanol gumming. Almost all pump gas in Ontario contains up to 10 percent ethanol. Ethanol attracts moisture and, left to sit, the fuel oxidizes into a sticky, varnish-like gum that clogs the tiny passages inside your carburettor. A clogged carb is the single most common spring repair we see, and it is almost entirely preventable.
Second, freeze and moisture damage. Water that condenses inside a fuel tank, a fuel line, or an engine block can freeze, expand, and corrode. Batteries left in the cold lose their charge and can crack. None of this is dramatic on any single cold night -- it is the slow accumulation over a five-month Ottawa Valley winter that does the harm.
When to Winterize
The rule of thumb is simple: winterize after your last mow but before the first hard freeze. In the Ottawa Valley that usually means sometime in mid-to-late October. Once nighttime temperatures start dipping below zero regularly, you want the machine already prepped and tucked away.
Do not wait until the snow is flying. Trying to run an engine to circulate stabilizer through a frozen carburettor in December defeats the purpose. Pick a mild fall afternoon, give yourself an hour, and do it properly.
Clean the Deck and Undercarriage
Start with the part everyone skips. Caked-on grass clippings hold moisture against bare metal all winter, and that is how rust gets a foothold on your deck. Disconnect the spark plug wire first -- always, before you go anywhere near the blade -- then tip the mower (carburettor and air filter side up, so you do not flood them with oil) and scrape the underside clean.
- Scrape out packed clippings with a plastic putty knife or a sturdy stick.
- Rinse, then dry the deck thoroughly. Trapped water is worse than dirt.
- Inspect the blade while you are under there -- nicks, dull edges, or bending are easier to deal with now than in the spring rush.
- A light wipe of oil or rust inhibitor on bare metal goes a long way over five months.
Why bother in the fall?
Because rust does not take the winter off. A clean, dry deck that goes into storage in October comes out in May ready to work. A grass-packed one comes out pitted.
Change the Oil and Filter While the Engine Is Warm
Used motor oil is contaminated with combustion acids and moisture that will sit and corrode internal engine parts all winter. Fall is the ideal time to change it because you can run the mower for a few minutes first -- warm oil drains faster and carries more of the gunk out with it.
- Run the engine for two or three minutes to warm the oil, then shut it off.
- Disconnect the spark plug wire.
- Drain the old oil into a proper container (most municipal depots and auto-parts stores in the Ottawa Valley take it for free recycling).
- Replace the oil filter if your engine has one.
- Refill with the grade your Briggs & Stratton manual specifies -- typically SAE 30 or a 10W-30 for small four-stroke engines.
Fresh oil going into storage means clean, non-corrosive lubricant coating your cylinder walls all winter instead of acidic sludge.
Fuel Stabilizer vs. Running the Tank Empty
This is the question we get asked most, so here is the straight answer. There are two legitimate approaches, and either works if you do it fully.
Option 1 -- Stabilize a full tank (our usual recommendation). Add a quality fuel stabilizer to fresh gas, fill the tank nearly full, and run the engine for five to ten minutes so the treated fuel works all the way through the carburettor. A full, stabilized tank leaves less room for condensation to form on the tank walls. Stabilizer keeps the fuel from oxidizing into gum for the whole winter.
Option 2 -- Run it dry. Shut off the fuel valve (if equipped) and let the engine run until it stalls from fuel starvation, then drain any remaining gas from the tank. This leaves nothing in the carburettor to varnish. The catch: small amounts of fuel residue can still gum the tiniest passages, and an empty system can let rubber gaskets dry out.
What you must never do is leave plain, untreated pump gas sitting in the tank and carburettor for five months. That is the recipe for the gummed-up carb that fills our spring repair bench.
If you are not sure your machine is fully cleared either way, that is exactly the kind of thing our free pickup-and-delivery winterization service handles for you. Just call 613-406-9246 and we will collect the mower from your driveway anywhere in town.
Remove and Store the Battery
If you run a riding mower or a zero-turn with an electric start, the battery needs attention. Cold drains a battery fast, and a discharged battery can freeze and crack.
- Disconnect the negative terminal first, then the positive.
- Remove the battery and store it somewhere cool and dry but above freezing -- a basement shelf is ideal, not the unheated shed.
- Top it up with a trickle charger or battery maintainer every month or so, or leave it on a smart maintainer all winter.
- Wipe the terminals clean and give them a light coat of dielectric grease to prevent corrosion.
Spark Plug Inspection and Storage
Pull the spark plug and have a look. A healthy plug has a light tan or grey tip; black, oily, or heavily worn means it is due for replacement -- cheap insurance for spring. Before you reinstall it, there is a worthwhile extra step many homeowners miss.
Pour a teaspoon of clean engine oil into the spark plug hole, then slowly pull the starter cord two or three times to coat the cylinder walls. This fogs the cylinder and protects against internal rust over the long winter. Then reinstall the plug (or a fresh one) and reconnect the wire.
Lubricate the Moving Parts
Cables, pivot points, wheel bearings, and throttle linkages all benefit from a shot of lubricant before storage. Anywhere metal moves against metal, a little oil or grease keeps it from seizing or rusting solid over the winter. Pay attention to the wheel height adjusters and the cable that engages the blade -- those are the ones that stick first when neglected.
Choosing the Right Storage Location
Where you park the mower matters more than people think. The ideal spot is dry, sheltered, and stable in temperature. A few Ottawa Valley realities to keep in mind:
- Dry beats heated. A dry shed or garage is fine even if it is unheated -- once the fuel is stabilized and the battery is out, cold alone will not hurt the machine. Moisture is the enemy, not the cold.
- Keep it off a bare concrete floor if you can. A scrap of plywood or a rubber mat underneath reduces condensation reaching the underside.
- Cover it -- but breathe. A loose breathable cover keeps dust and drips off. A sealed plastic tarp traps condensation against the metal, which is worse than no cover at all.
Rodent Prevention
Out here, this is not optional. Mice love a quiet shed for the winter, and a lawn mower is prime real estate -- they nest in the housing, chew through wiring and fuel lines, and pack the muffler and air intake with bedding. We pull rodent nests out of machines every single spring.
- Stuff a clean rag or steel wool into the exhaust outlet and the air intake (and write yourself a note to remove them before starting in spring).
- Keep the storage area free of birdseed, pet food, and grass clippings that attract them in the first place.
- A few mothballs or peppermint-oil cotton balls around the mower help deter them.
- Avoid leaving the mower right against a wall where mice run -- a little open space makes it less inviting.
Spring Startup Checklist
Come May, a properly winterized mower wakes up easily. Run through this before the first pull:
- Remove any rags or steel wool you stuffed in the exhaust and air intake.
- Reinstall the battery (positive terminal first), fully charged.
- Check the oil level and top up if needed.
- If you stored it dry, add fresh gas. If you stored it full and stabilized, the fuel should still be good.
- Check the air filter -- replace it if it is dirty.
- Confirm the spark plug is seated and the wire is reconnected.
- Give the blade a final inspection and tighten the bolt.
- Prime and pull. It should start within a few attempts.
Why Professional Winterization Is Worth It
None of these steps is rocket science, but doing all of them well takes time, the right oil and stabilizer, a place to drain fluids, and a bit of comfort working around the engine. If that is not your idea of a good fall Saturday -- or if last spring's hard-starting mower told you something was missed -- it is worth letting a shop handle it.
As your local authorized Briggs & Stratton dealer in Arnprior, we winterize your mower properly: fresh oil and filter, stabilized or cleared fuel, fogged cylinder, inspected plug and blade, battery maintained, and stored ready for spring. And because we offer FREE pickup and delivery right in town -- something most shops charge extra for -- you do not even have to load it into the truck.
We serve Arnprior, Braeside, Burnstown, White Lake, Pakenham, Renfrew, Almonte, Carleton Place, Calabogie, Kinburn and the wider Ottawa Valley. Book your mower's winterization before the first hard freeze and let it spend the off-season in good hands. Call us at 613-406-9246 and we will come get it.