It’s one of those end-of-season habits that feels responsible. After the last mow of the year, you tip the lawn mower onto its side, scrape the caked grass off the underside of the deck, and roll it into the shed for the winter. Then spring comes, you pull the cord, and the mower coughs, sputters and blows a cloud of white smoke across the driveway. Plenty of homeowners have lived exactly that, and the cause is almost always the same: the mower was tipped onto the wrong side.
Cleaning the deck is a good idea. Doing it the wrong way round is one of the most common ways to make a gas mower refuse to start.
Why the side matters
A four-stroke gas mower keeps its engine oil in the crankcase at the bottom of the engine. Tip the machine the wrong way and that oil runs where it was never meant to go: into the air filter and the carburetor. Fuel can leak out too. Nothing seems wrong at the time. The trouble shows up at the next start, when the engine tries to burn the oil it swallowed.
The classic signs: thick white or bluish smoke, an engine that stalls or refuses to catch, and an air filter soaked in oil.
The right way to tip a mower
- Disconnect the spark plug wire first, so the blade can’t turn over the engine by accident.
- Find the air filter and the carburetor, and keep that side facing up. On many mowers the safe rule is also spark plug up.
- Check the owner’s manual if in doubt: some manufacturers specify a side, and a few recommend tilting the mower back on its handle instead.
- Scrape the deck with a plastic or wooden scraper rather than metal, which strips paint and invites rust.
If it’s already smoking
Don’t panic, and don’t keep yanking the cord. Set the mower upright on level ground and leave it for half an hour so the oil can drain back down. Remove the air filter: a paper filter soaked in oil needs replacing, a foam one can be washed and dried. Check the oil level and top up if needed. Then start it and let it run; some smoke at first is normal while the last of the oil burns off. If it still won’t start or keeps smoking heavily, that’s a job for a small-engine repair shop.
Putting the mower away for winter
Fall is the moment to do the rest of the job properly. Gasoline left sitting for months goes stale and gums up the carburetor, so either run the tank dry or add fuel stabilizer and run the engine for a few minutes to circulate it. Clean and dry the deck, change the oil, sharpen the blade so it’s ready for spring, and store the mower somewhere dry. For battery mowers, remove the battery and keep it indoors, above freezing.
The same end-of-season clean-up applies to the paths and patio, where gardeners have swapped the weedkiller for the pot they drain after dinner.
Air filter up, oil in the crankcase, fuel stabilized. The mower starts first pull in April. That’s the trick.
