How will E10 petrol affect your STIHL chainsaw
We know there have been many debates about E10 petrol and how it affects petrol tools. E10 petrol became the standard grade in the UK from summer 2021.
E10 petrol contains up to 10% renewable ethanol. This is intended to help reduce CO2 emissions, but we know that some of you have concerns about how this affects your petrol tools. We recommend in all of our owners’ manuals that you should only use high-quality brand-name petrol with a minimum octane rating of 90, but we can reassure you that petrol with an ethanol content of 10% or less, like the new E10 petrol will not cause a problem with your STIHL petrol tool.
In fact, our STIHL M-Tronic engines can still deliver full power when run using petrol with an ethanol content of up to 25% (E25).
However, petrol with an ethanol content of more than 10% can cause running problems in engines with a manually adjustable carburetor so should not be used in such engines.
As with any petrol, we would still recommend not storing your machine with E10 petrol in it, to avoid any blockages in the fuel delivery parts of the tool. We also recommend that you store E10 fuel for no longer than 30 days in order to minimize the degree of fuel segregation. This is where the moisture in the air binds with the ethanol and settles on the bottom of the canister. This can cause running problems and shaking the container does not completely resolve fuel segregation.
In some tools, it may also be necessary to readjust the carburetor to compensate for the changed composition of the fuel. We recommend that you visit a STIHL Approved Dealer for this.
Of course, if you are concerned about the use of ethanol in your machines, then you can always consider our premium, patented fuel formula, MotoMix. STIHL MotoMix is completely free from ethanol and has virtually no olefins or aromatic compounds. Emission-wise, this makes it a cleaner, more environmentally-friendly choice than regular fuels, plus it lasts longer so you can store it for up to 5 years, which is handy as MotoMix is available in 200 litre drums!
However, if you still want to use standard petrol, we are happy to reassure you that the new E10 petrol is fine to use in your STIHL petrol tools. You can search for the Instruction Manual for all current STIHL tools and some older versions here if you want to check any fuel recommendations.
We have included some additional Frequently Asked Questions below, and you can always visit your local STIHL Approved Dealer if you need any further information.
This is possible, particularly in some older machines. Ethanol contains oxygen so when the ethanol content is higher, so is the oxygen content. This means that more fuel needs to be burned to compensate so it will be slightly less fuel efficient to use E10 fuel. STIHL MotoMix is ethanol-free so will automatically be more efficient.
E10 fuel has been available in a number of other countries, including the US and Australia for a number of years already so we have real-world experience of E10 petrol being used with STIHL engines without issues.
STIHL HP Ultra does contain a fuel stabiliser which is designed to slow the rate of deterioration in fuel but by its nature, ethanol is hygroscopic, which means it absorbs moisture more easily and will go stale quicker then fuels without ethanol, such as MotoMix. Even if you use HP Ultra oil with E10 fuel, we still recommend not storing it for longer than 30 days.
MotoMix itself will not cause fuel lines to harden. The hardening is likely to have been caused by the ethanol content in the previous fuel and would have been evident at some point in the future without MotoMix being used. If there is any concern over the condition of the fuel lines, then we would recommend replacing them with the current ethanol-resistant parts as part of a service or repair of the machine.
Both STIHL MotoMix and Moto4Plus, our fuel for small 4-stroke engines, are made in Germany.
