What is ethanol & why is it in petrol?
Because of this, the UK government introduced financial incentives for suppliers of petrol to use a percentage of ethanol in their blends.
There are pros and cons of using ethanol in various blends, but in terms of performance, 3 things stand out:
- Ethanol is a great oxygenate which helps to give a cleaner burning fuel and increase power from the engine if fuelling can be adjusted to suit. E85 (85% ethanol, 15% petrol) is often used in motor sport for this reason.
- Ethanol contains less energy than regular petrol so as you increase the level of ethanol. Fuel consumption (MPG) will decrease.
- Ethanol is aggressive to fuel system components and will absorb moisture from the atmosphere which can cause issues which are mainly seen in engines fitted with a carburettor (vented fuel systems).
As a rule of thumb, most vehicles produced since 2002 are ok to use E10 fuel and all cars produced after 2011 had to be E10 compatible.
Modern cars have a sealed fuel injection system which means the atmosphere cannot oxidise the fuel at the same rate. Cars also have sophisticated fuelling systems which can compensate for the different qualities of fuel, whereas the small machinery only has one setting and relies on the fuel quality being consistent.
Whilst using fresh fuel containing ethanol is unlikely to cause any performance issues with your garden machinery, in reality, it is very rare that fresh fuel is always used. Although most garden machinery uses small volumes of fuel, it is more practical for the operator to purchase their fuel in bulk. Can you remember when you last filled up the can of fuel which is in your shed? Most manufacturers state fresh fuel should be less than 30 days old and kept in a sealed container.
Use ethanol-free fuel such as Aspen and you will also benefit from reducing toxic emissions and not needing to mix 2-stroke fuel.
If you continue to use regular pump fuel, always keep your fuel fresh, never buy supermarket fuel (this seems to cause more problems) and never use fuel over 30 days old – whether in the fuel tank or from a storage container.