Why won't my lawn mower start after winter?
Issues when starting lawn mower engines are common in spring. If you're getting your mower out of storage for the start of the grass cutting season and the engine won't start, it's most likely that the fuel in your engine has gone stale over winter.
When fuel is stored in small quantities it gradually goes stale. When this happens the fuel turns a brown colour and in extreme cases can become sticky.
If this happens, it's much harder for the engine to ignite and therefore the engine becomes difficult, if not impossible, to start.
How to fix an issue with stale fuel
To fix a stale fuel problem you will need to drain the old fuel from the petrol tank. Please TAKE CARE. Remember, you are dealing with a flammable substance.
Once the fuel has been fully drained, fill the tank with fresh fuel. If you have leftover fuel in a fuel can from last year, it's also just as likely for the same to have happened.
It's best to use fresh fuel from a petrol station or from your local garden machinery supplier.
What to do if your engine still won't start after replacing the fuel
If you find that your mower still won't start after replacing the fuel, it's possible there is sufficient stale fuel left in the carburettor to prevent the engine from starting.
If this happens, we would recommend contacting your local garden machinery supplier to investigate further. It's possible your carburettor needs professionally cleaning.
How to prevent future issues with stale fuel
Fuel that contains ethanol, such as the E10 fuel which you can buy from a fuel station, is subject to becoming stale if left. You can:
- Use clean burning fuel, such as Aspen or STIHL Moto4Plus which don't contain ethanol and will remain fresh for several years
- Use an additive to slow the process of fuel becoming stale
- Fully drain your fuel before storing your mower for the winter
What if it's something else
The most common cause of your mower engine not starting after a long period of storage is stale fuel, but there are many other possible reasons there could be a fault.
Our advice is to contact your local lawn mower servicing provider for a professional inspection.
Posted: 11 August 2022