Taking time to prepare your lawn mower for winter will help ensure a smooth start the following spring.
Important safety precautions: You must disconnect the spark plug on petrol mowers before winterising or carrying out any work on the machine; for electric lawn mowers, disconnect the power cord; and for cordless lawn mowers, remove the battery.
Before storing your lawn mower, you first need to give it an especially thorough clean after the last cut of the year. Any old grass residue adhering to the mower housing can be removed using a brush or wooden scraper; you should also avoid leaving any grass residue in the cooling fins or the exhaust area. The best way to clean your machine is simply with water or STIHL cleaning agent and a brush. If it is very dirty you could use a garden hose, but be careful – after all, you want your lawn mower ready for storage, not damaged. With that in mind, avoid aiming strong jets of water at the bearings, seals or engine parts. Remember that when you are clearing the dirt from the underside of a petrol mower’s housing it’s important to tip the mower back in such a way that the spark plug points upwards. If you tip the mower to the side, oil can get into the air filter or exhaust, which risks seriously damaging your machine.
Take a close look at the cutting blade. If you can see any cracks or notches: you should first have the blade sharpened or replaced at your preferred STIHL dealer. In any case, it is generally advisable to entirely remove the blade and sharpen it, or to have it professionally sharpened and balanced – in fact, we recommend this not only when winterising, as it should preferably be done regularly after around 25 hours of use.
Remove the spark plug and see if it needs cleaning or changing – it should be replaced after 100 hours of use, as spark plug faults can cause the mower to run poorly. Once you’ve done that, the next maintenance step is to pour approximately 3 cc of engine oil into the spark plug opening, then run it through the engine without the spark plug installed by pulling the starter cord a few times. Refit the spark plug afterwards. Doing this keeps the engine well protected while it’s in storage.
With this maintenance work completed, your lawn mower is fit to get through the winter months in good condition. Now you need a suitable place to store it for the cold season: this should be a dry, dust-free space, and the lawn mower should preferably be covered up and then stored in its normal position on all four wheels.
It’s important to ensure that the fuel tank of your lawn mower is empty before the winter break. Any remaining petrol will degrade over the winter, meaning you may have problems starting your mower if you leave petrol in the tank until spring. If there is only a little fuel in the tank after you’ve done the last cut, we recommend leaving the lawn mower running until the engine stops by itself.
When preparing your petrol lawn mower for winter, it’s important to ensure the oil level is right. Your machine should always be maintained in good working order – even while it is in storage for the winter. If the oil needs changing towards the end of the season, you should do it immediately rather than putting it off until after winter. Your STIHL dealer will of course be happy to help you with the oil change, though if you prefer to change the oil yourself, please observe the operating instructions and use the recommended brand oil.
Many elements of preparing a cordless lawn mower for winter storage are the same as for a combustion engine or electric lawn mower: cordless lawn mowers should also be cleaned thoroughly and the moving parts greased. But before you do any of that, remove the battery from your cordless lawn mower.
You should charge the battery to around 40-60% (2 LEDs), then store it separately from the lawn mower in a dry room at 10 to 15°C: these conditions ensure the battery remains undamaged, retains its storage capacity and is fully operational next season. If the battery in your cordless lawn mower is fixed and not removable, you need to store the machine as a unit – which means storing the complete lawn mower in a warm, dry place.