Putting the lawnmower away for winter: fuel, blade, and battery care
Put the mower away wrong and spring starts with a repair. Put it away right and the routine is short: settle the fuel question from the manual, change the oil, inspect the blade, and store the battery the way its chemistry requires. The catch is that gas walk-behinds, riding mowers, and battery mowers diverge at almost every one of those steps, so pick the machine first and follow only its column.
Job summary
Difficulty: basic owner maintenance, within the operator's manual. Tools: the manual, fuel stabilizer if your fuel path calls for it, oil and a filter where fitted, a container for old oil, and a wrench for the blade and battery cables. Hire-a-pro line: a blade you cannot remove safely, a battery showing damage, or any fuel-system fault is dealer work, not a storage task.
Three machines, three routines
| Step | Gas walk-behind | Riding mower | Battery mower |
|---|---|---|---|
| Fuel | Stabilize and store full, or run dry — per the manual | Same fuel decision, per the manual | No fuel system to treat |
| Battery | Usually none fitted | Remove the lead-acid battery or keep it charged; grease fittings and check tire pressure | Pull the lithium pack and store it indoors at partial charge |
| End-of-season service | Oil change; remove and inspect the blade; clean the deck | Oil and filter while the engine is warm; blade inspection | Clean the deck; blade inspection |
Fuel: stabilize and fill, or run it dry
This is the step owners argue about, and both sides have manufacturer backing. Both fuel paths are manufacturer-approved: stabilize and store full, or run the fuel system dry — whichever the manual calls for. The manual for your engine decides, not habit and not a neighbour's routine.
On the stabilize path, the Briggs & Stratton guidance is specific. Add fuel stabilizer per the package directions — fuel can begin to degrade in as little as 30 days — and store the mower with a full tank of treated fuel, which prevents moisture condensing in the tank. Run the mower for a few minutes so the treated fuel circulates through the system. An alcohol-free fuel stabilizer and ethanol treatment keeps fuel fresh for up to 24 months and eliminates the need to drain fuel before storage.
On the run-dry path, the point is the opposite: no fuel left sitting in the system over winter. Either way, do half of one and half of the other — an untreated half tank combines the drawbacks of both.
The storage procedure, in order
- Read the fuel section of the manual. Mark which path it specifies: stabilize-and-fill or run-dry. Success looks like a decision written down before any fuel is touched.
- Treat or drain the fuel. For stabilize-and-fill, add stabilizer per package directions, fill the tank, and run the engine a few minutes to circulate it. For run-dry, follow the manual's draining or run-out procedure. Success looks like a full treated tank, or an empty system — never an untreated part tank.
- Change the oil while the engine is still warm. Follow the operator's manual for oil type and amount, and change the filter where one is fitted. Do not store the engine dirty. Success looks like clean oil at the correct level on the dipstick.
- Remove and inspect the blades. Briggs & Stratton includes blade removal and inspection in the winter sequence. Look for damage and dullness now, while sharpening or replacement can happen over winter instead of on the first mowing day. Success looks like a blade that is either fit to refit or already on the replace list.
- Clean the deck. The battery-mower guidance names deck cleaning directly, and the same cleaning step belongs in the gas routine before parking. Success looks like a deck scraped clean before the machine is parked.
- Deal with the battery — by type, below. Success looks like no battery left connected and forgotten in a cold machine.
- Park it dry and covered. Riding mowers add two small jobs at this point: grease the fittings and check tire pressure. Success looks like a clean, serviced machine that needs nothing before its spring check.
Batteries: lead-acid out and cool, lithium in and partial
Lead-acid and lithium packs want opposite winters, and mixing the routines up is the common storage error.
Lead-acid (riding mowers): disconnect the negative battery cable first, then the positive. Clean the terminals, and store the battery in a cool, dry place — away from gas cans, water heaters, and furnaces. The riding-mower alternative is to leave the battery in place but keep it charged; a removed, stored battery and a maintained one are both defensible, an ignored one is not.
Lithium (battery mowers): pull the battery from the machine, store it indoors somewhere dry, and store it at partial charge — not full, not empty. The pack lives in the house for the winter; the mower body, deck cleaned, can stay in the shed.
The spring-start checklist this storage sets up
- Refit or reconnect the battery — for lead-acid, the removal order reverses on installation.
- Check the oil level before the first start; storage ended with clean oil at the correct level, so confirm it still reads that way.
- Confirm the blade was inspected, sharpened, or replaced over winter — not discovered dull at the first cut.
- For a run-dry machine, add fresh fuel; for a stabilized machine, the treated full tank is the starting point the storage method promised.
That short list is the payoff. A mower stored by its own manual's routine starts the season as a checklist, not a diagnosis.
— Tom Reilly, Home & DIY Writer