Can I use E10 fuel in my lawnmower?

What is E10 petrol?

E10 petrol was introduced into the UK from 1 September 2021 and is now the standard 87 octane regular unleaded petrol that you find in a filling station. E10 replaced the old E5 regular octane unleaded petrol.

E10 petrol is made up of 90% petroleum-based petrol and 10% ethanol. Ethanol is an alcohol-based fuel produced from the fermentation of a range of plants.

Can I use E10 petrol in my lawn mower?

Most "modern" engines will be compatible with E10 fuel, but to be certain if your engine is compatible you will need to refer to your operators' manual. Many garden machinery manufacturers have shared advice around E10 fuel.

For example, Honda have said,

"All Honda Lawn and Garden products with petrol engines, produced for the UK market since 1993, are compatible with E10.".

Hayter have said,

"All current production machines using Hayter, Briggs & Stratton, Honda, Kohler and Kawasaki engines can safely use E10 fuel, but no higher. For older machines we recommend that you refer to your engine operators' manual for guidance."

As a general guide, engines produced from the following dates are compatible for use with E10 fuel:

• Year 2000 Hayter
• Year 2000 Briggs & Stratton
• Year 2000 Honda
• Year 2011 Kawasaki
• Year 2020 Kohler

How will E10 fuel affect my garden machinery?

If your engine is not compatible with E10 you may have issues with the fuel reacting with rubbers and plastics within the engine.

For all engines, regardless of E10 compatibility, ethanol fuel blends will absorb water from the atmosphere and this may cause corrosion of fuel system components. The corrosion can cause passages in the carburettor to become blocked and, regardless of whether or not corrosion occurs, the engine will not run on fuel containing water.

Since most carburettors and their petrol tanks are vented to the atmosphere in some manner there is nothing to prevent petrol from absorbing moisture over time once it is in the engine.

Furthermore, temperature variations can cause condensation to collect inside your storage container if it is not properly sealed. Fuel should be stored in dry areas with low humidity. Ethanol will absorb any condensation that forms inside storage containers thus contaminating your fuel.

To make matters worse, petrol naturally deteriorates over time. Deterioration begins with the most volatile compounds evaporating and once evaporation reaches a certain point it will be impossible to start the machine. This is often the reason why people found lawnmowers difficult to start in the spring, even more E10.

As more compounds evaporate, the petrol will form brown gummy deposits in the fuel system which, given enough time, will become a hard varnish.

These gummy deposits and varnish can block passages in the carburettor causing the engine to run poorly, or in the worst cases preventing it from running entirely. The deposits can also cause fuel leaks. A carburettor will often have to be professionally cleaned to remove these deposits or even replaced.

Good fuel management is the key to preventing these types of problems.

How to minimise fuel system problems

Using fresh petrol that is less than 30 days old will help prevent water absorption from becoming a problem, but using a supply of fuel within 30 days isn't practical for most people.

Instead, fuel additives, also known as stabilisers, can be used to minimise the oxidation and water absorption rate of petrol and extend its storage life. A fuel stabiliser should always be added to the fuel when the fuel is purchased.

Clean burning fuels such as Aspen, STIHL Moto4Plus and STIHL MotoMix, Husqvarna Power 4 and Husqvarna XP Power 2 are free from ethanol and can be used as an alternative to fuel bought from a filling station. If you're interested in buying or finding out more about these clean burning fuels, get in touch or visit one of our showrooms.