Will my lawnmower run on E10? Can I use new petrol in garden machinery in UK - and how to check

A new petrol - E10 - is now the standard unleaded option at filling stations across Great Britain.

The change will see the standard petrol grade change from E5 to E10 in fuel courts across England, Scotland and Wales.

Northern Ireland will make the switch to E10 petrol "in early 2022", states the UK government.

And, while many are checking to see if their car will take the new fuel, some are wondering what impact this will have on lawnmowers.

Here’s a look at whether petrol lawnmowers and other garden machinery dependent on fuel will be able to run on E10 - and if it’s safe to mix.

What is E10?

In a bid to reduce carbon emissions from road transport, the UK government is introducing a new standard petrol to be used at filling stations.

The old standard unleaded petrol, known as E5, contains up to 5% renewable ethanol.

E10 - the new standard unleaded petrol - contains up to 10% bioethanol, taken from renewable sources such as sugar beet.

The switch from E5 to E10 is expected to reduce a car’s CO2 emissions by around 2%, according to the Department for Transport.

It estimates that changing to E10 will cut the UK’s CO2 emissions by 750,000 tonnes a year - equivalent to removing 350,000 cars from the road.

But is it safe to put into lawnmowers?

Will my lawnmower run on E10?

Whether your lawnmower is compatible with E5 or E10, owners should exercise caution when putting fuel into their garden machinery.

This is because ethanol attracts water which can cause problems in starting or running the equipment, or even damage the lawnmower’s fuel system.

Ethanol absorbs moisture from the atmosphere which could lead to a corrosion of parts in the fuel system, posing a safety risk and problems in running smoothly.

These problems tend to occur if the fuel is left in the tank for long periods of time, particularly over the wetter and colder months of the year.

The official line from the UK government is to check the product manual or ask the manufacturer or dealer before switching from E5 to E10 petrol.

How can I check if my lawn mower will work on E10?

Check the product manual to see if your lawnmower is compatible with E10.

If it is compatible with E10, it still might not be the best option if your lawnmower is going to be left idle for weeks and months on end through the winter months.

Under a section headed ‘avoiding fuel related problems’, Honda states not to use gasoline "containing more than 10% ethanol in your Honda lawn mower".

For storage or more than 30 days, Honda recommends adding a gasoline stabilizer to the fuel tank and filling the tank as air in the tank will "promote fuel deterioration during storage".

A stabilizer is also recommended by Mowers Online, as "ethanol causes multiple problems for small petrol engines and you shouldn’t leave it in the tank".

AA technical specialist, Greg Carter, warned against using E10 in lawnmowers and recommended only buying the ‘super unleaded’ for garden equipment.

"Petrol powered garden machinery and generators are also likely not to be compatible, so these should use super unleaded after September," Carter told ThisIsMoney.com.