E10 in a Chainsaw and Winter Storage (UK)

Can You Use E10 in a Chainsaw, and How Long Does Two-Stroke Mix Keep?

Check your manual: GOV.UK says chainsaws may not be compatible with E10, and E5 "super" is sold where a station offers two grades. Mix only what you'll use in a few weeks: STIHL's manuals say not to keep fuel mix longer than 30 days. Kit sitting a month or more: lay it up as its manual says.

Everything below was checked on GOV.UK and the makers' own manuals and support pages on 25 October 2026. Follow your own machine's manual where it says something different.

E10 or E5?

E10 is the standard petrol. "Standard grade (95 octane) petrol became E10 in Great Britain in September 2021 and in Northern Ireland in November 2022" (GOV.UK: E10 petrol explained, updated 2 November 2022).
Your kit may not be compatible. GOV.UK lists "petrol-powered garden equipment or machinery, such as lawnmowers and chainsaws" among the equipment that may not be compatible with E10, and says "Owners and operators should check their manual or ask the manufacturer or dealer before using E10" (GOV.UK).
Where to get E5. E5 is the "super" grade (97+ octane): "Petrol stations that offer 2 grades of petrol will stock E10 (95 octane) and E5 (97+ octane) petrol", and "Some rural, remote or very small filling stations may sell only either E5 or E10 petrol as standard" (GOV.UK). The pump label says which is which.

Fuel by How Often the Kit Is Used

Kit used every day (the felling saws that work right through the winter): mix small batches often, so the fuel is always fresh.
Kit used now and then (a backup saw, a hedge cutter, a pole saw, a brushcutter): mix even smaller batches, or use ready-mixed alkylate fuel in a sealed can. It keeps far longer than a home mix: STIHL's manuals give up to 5 years for STIHL's own, against 30 days for a home mix, and STIHL GB says that's "unopened in the original container" (STIHL GB: what is an alkylate fuel?). Go by what the maker says on the can.
Mix small, date the can, keep it sealed. STIHL's manuals say: "Fuel mixture deteriorates with age – mix only as much as needed for a few weeks. Do not store fuel mixture for longer than 30 days. The fuel mixture can become unusable more quickly if exposed to light, sunlight or low or high temperatures." Store it "in approved safety fuel canisters only in a dry, cool and secure place protected against light and sunlight", and shake the can before you fill up (STIHL FS 45 instruction manual, section 7.3; the BR 200 manual says the same). Write the date you mixed it on the can.
The mix ratio is the one your manual and your two-stroke oil give. Don't guess it.

Winter Storage for Seasonal and Backup Kit

If your felling saws and chipper keep working through the winter (see our winter work guide), laying up is for seasonal and backup kit (hedge cutters, brushcutters, pole saws, a spare saw) and for kit sitting while it's listed for sale.

Do what the manual says. STIHL's manuals, for example, say that "If out of use for periods of about 30 days or longer":

drain and clean the fuel tank in a well-ventilated area, and dispose of the fuel properly;
if a manual fuel pump (primer bulb) is fitted, press it at least 5 times;
"Start the engine and run it at idling speed until it stops";
clean the machine thoroughly, especially the cylinder fins and the air filter;
store it in a dry and secure place, out of the reach of children (STIHL FS 45 instruction manual, section 15).

If your manual gives a different method, follow it.

Starting a Saw or Trimmer After Winter

Husqvarna UK's list for its trimmers and brushcutters, "Before the first use after storage", includes "Inspect the cutting attachment", "Check all screws and fasteners", "Refill with fresh fuel (petrol models)" and "Start the machine and check that it operates normally" (Husqvarna UK: how to store a grass trimmer and brushcutter for winter, 30 July 2026). For a chainsaw:

Old fuel out, fresh mix in. Husqvarna UK says "Old or stale fuel can clog the fuel system", that a saw with old fuel "may start briefly and then stop", and that "Damage caused by stale fuel is not covered by warranty" (Husqvarna UK: why your chainsaw starts and then dies, 9 December 2025). If it was put away with fuel in the tank, empty it, dispose of the fuel properly and refill with a fresh mix.
If it dies when you tilt it, Husqvarna UK says "the issue could be with the fuel filter inside the tank": check for a missing or damaged fuel filter, damaged fuel lines and leaks, and take it to a dealer if you think the fuel lines are damaged or leaking.
Then do the checks your manual lists before you start work.

Cold Mornings: Hydraulics and Diesel

Let the hydraulics warm up before you judge the machine. Avant's loader manual says "Hydraulic oil temperature influences the hydrostatic drive system of the loader", and: "When the ambient temperature is below 5 °C, make sure the general response to drive pedals is normal. If the drive feels sluggish, allow the hydraulic system to warm up by letting the loader to run at idle until the drive system works normally" (Avant 755i/760i operator's manual, 2025, page 93). Chipper manuals differ, so follow yours, and on a cold morning let the hydraulics warm before you decide a chipper's roller feed is slow, whether you're working it or a buyer is trying it.
Milky hydraulic oil. When you do the daily oil-level check in our chipper maintenance schedule, look at the oil as well. MTS Systems, a maker of hydraulic test equipment, says "Clean fluid is almost clear to amber in color", "A milky appearance usually suggests water contamination" and "If the fluid looks milky, take immediate action to avoid severe damage to your hydraulic system" (MTS: how to tell if hydraulic fluid has gone bad). Don't work the machine until a dealer or fitter has checked it.
Water in the diesel. Hatz's manual for its 1B30E and 1B50E diesel engines says "Water in the fuel tank collects at the lowest point of the fuel tank in the water separator", and "the water separator should be checked at least once a week" (Hatz 1B30E/1B50E manual, section 7.7). Avant's loader manual says "Water in fuel can cause significant damage to the injection system of the engine"; on its loaders the separator is part of the main fuel filter, and a dashboard light shows when it needs draining (page 135). Check and drain yours as its engine manual says, with the engine off, and dispose of what comes out properly.

Selling Kit Over the Winter

If you list petrol kit while it's laid up, say in the advert how it was stored and when it last ran, and be ready to start it for a buyer. Our seller's guide covers the photos, hours and paperwork to include, and our chipper maintenance schedule covers storing a chipper between jobs.