How to Store Your Petrol Lawnmower Over Winter

Every spring, Paul sees dozens of mowers that won't start — and most of the time, the problem started months earlier when the mower was put away for winter without any preparation.

Thirty minutes of work in autumn saves you a carburettor rebuild in March. Here's exactly what to do.

Drain or Stabilise the Fuel

This is the single most important step. Petrol goes stale within 30 days and leaves a varnish-like residue that clogs the carburettor jets. You have two options:

• Drain the tank completely and run the engine until it stops — this burns off any remaining fuel in the carburettor
• Add fuel stabiliser to a full tank and run the engine for 5 minutes to circulate it through the system

Change the Oil

Don't leave old oil sitting in the engine all winter. Used oil contains acids and moisture that corrode internal engine parts over months of sitting. Drain it while the engine is still warm (oil flows better) and refill with fresh oil. You don't even need to put the correct amount in — just enough to coat the internals. Top it up properly in spring.

Remove and Inspect the Spark Plug

Take the spark plug out and squirt a small amount of engine oil into the cylinder through the spark plug hole. Pull the cord a couple of times to distribute the oil — this prevents the piston rings from sticking and protects the cylinder bore from corrosion. Refit the plug loosely or cover the hole to keep moisture and debris out.

Clean the Deck and Blade

Scrape off all built-up grass from under the deck. Grass holds moisture against metal, which accelerates rust. If the blade is in good condition, leave it fitted. If it needs sharpening, now is a great time — beat the spring rush.

Battery Care (If Applicable)

If your mower has an electric start, remove the battery and store it somewhere dry and frost-free. A trickle charger is ideal for keeping it topped up over winter. A dead battery left in the cold will often refuse to hold a charge come spring.

Storage Location

Store the mower in a dry shed or garage. If you have to leave it outside, invest in a proper breathable cover — avoid plastic sheeting, which traps condensation underneath and causes more rust than no cover at all.

• A dry garage or shed is ideal
• Avoid damp stone floors — put the mower on a pallet or wooden board
• Never store near fertiliser or chemicals — ammonia fumes corrode engine parts

What Happens If You Skip This

Paul regularly strips down carburettors clogged with stale fuel residue. It's the most common repair he does in spring. A carburettor clean and rebuild costs significantly more than the five minutes it takes to drain the fuel in autumn.