Since the introduction of E10, anyone who mixes the fuel for their chainsaws using petrol from the petrol station and two-stroke oil has no doubt wondered whether E10 is also suitable for use in chainsaws, clearing saws and other similar tools. We have summarised the key facts about E10 for you below.
What is E10?
The designation E10 is an abbreviation. The “E” stands for the ethyl alcohol (i.e. ethanol) which is added to the petrol. The number 10 indicates that the mixture may contain up to 10% ethanol. Ordinary premium-grade petrol – containing a maximum of 5% ethanol – is also still available.
Use of E10 in STIHL power tools
As a rule, fuels containing up to 5% or 10% ethanol are compatible with all STIHL chainsaws and power tools.
A carburettor adjustment may be necessary to compensate for the change in fuel composition. For this, we recommend visiting a STIHL dealer.
A word of warning during longer idle periods
While fuel is used up within a matter of weeks during the warm seasons, it remains significantly longer in the canister, tank and carburettor during periods when the tools are not in use (e.g. brush cutters during the winter months). During this time, oxygen and moisture from the air seep into fuel containers and systems, which can change the composition of the mixture when it comes to fuel from the petrol station.
Additives or manufacturer blends serving to enhance the fuel properties, such as antioxidants and anticorrosive agents, may fall prey to these effects and be cancelled out of the mixture.
In addition, gum deposits can also form. Gums are residues that are left behind by fuels after they have evaporated. Having gum in your fuel can result in deposits building up in the engine’s combustion chamber or lead to injectors and filters becoming stuck or plugged up, and should therefore be avoided at all cost.
In the case of two-stroke mixtures with fuels that contain ethanol, the oil and petrol can begin to separate already after a relatively short period of time. STIHL recommends storing a two-stroke mixture prepared using E10 fuel for no more than 30 days to minimise phase separation. In this context, phase separation means that the ethanol absorbs moisture from the air and settles to the bottom of the canister. As a result, the two-stroke oil is not evenly distributed throughout the fuel and the engine lacks the necessary lubricant, which can cause it to run roughly. As experience has shown, the lack of lubrication and cooling will result in the pistons seizing up by the second tankful at the latest. Phase-separated fuel is no longer suitable for use even after being shaken vigorously.
In general, unsuitable fuels or a fuel/oil mixing ratio that deviates from the specification can result in engine damage. That is why when it comes to playing it safe with your STIHL products, STIHL MotoMix fuel is always the best choice. They are specially formulated for these engines and ensure excellent performance and a long service life.
Specifically, this means the following:
- up to 70% fewer emissions
- best start response and top engine performance thanks to powerful, high-quality components
- optimum combustion properties maximise your engine’s service life
- largely benzene-free
- STIHL MotoMix remains stable for a long time − storage period of five years*
On our website, you will find all of the information on STIHL fuels, oils and lubricants.
*In a cool, dry storage space in the tightly closed original container.