We are constantly been contacted by concerned customers asking what type of fuel should they use in their 4 stroke power equipment.
We have listed below information obtained from manufactures web sites and hope this helps in some way. Also attached is information from BP explaining Fuel Life in Tanks as well as effects of E10 unleaded in older machines.

Honda Fuel Recommendations

What fuel should I use in my Honda engine?

Honda engines are designed and certified to run on regular unleaded gasoline.

Gasoline is allowed, by regulation, to contain a variety of additives. The same regulation limits how much of some additives, such as alcohol, can be included in the fuel and still allow it to be sold as gasoline. If you look in a Honda product owner’s manual, you will see that a maximum of 10% ethanol is allowed in gasoline (other oxygenates are also listed). Honda engines are designed for good performance and efficient operation using gasoline containing from 0 to 10% ethanol.

Stihl Fuel Recommendations

Stihl is a maker of small hand held equipment such as chainsaws, string trimmers, blowers, etc. In the Frequently Asked Questions section of the Stihl website there is a question on the use of ethanol blended fuel.

Will a 10% (E10) blend of ethanol hurt my chain saw, trimmer, or blower?

All STIHL gasoline powered engines are OK for use with up to a 10% (E10) blend of ethanol in gasoline

John Deere Fuel Recommendations

Use only fuels recommended in Operator’s Manuals:

Use regular grade unleaded fuel with the lowest octane rating possible. Fuel blends containing up to 10% ethanol (E10) or up to 15% methyl tertiary butyl ether (MTBE) reformulated fuel are acceptable.

DO NOT use fuels with more than E10, (E85 should not be used because it is 85% ethanol and 15% gasoline). DO NOT use fuels with more than 15% MTBE reformulated fuel. Incorrect fuel will damage engine and or fuel system. Also do not use fuel or additives containing methanol as engine damage can occur.

Briggs and Stratton Fuel Recommendations

Briggs & Straton is one of the largest makers of small engines. Their engines can be found on power equipment such as lawn mowers, pressure washer, snow blowers, etc. According to their website E10 unleaded is allowed in all four stroke and two stroke engines.

All 4 stroke cycle spark ignited engines

Gasoline with up to 10% ethanol (gasohol) or up to 15% MTBE (methyl tertiary butyl ether), is acceptable.

All 2 stroke cycle spark ignited engines

Gasoline with up to 10% ethanol (gasohol) or up to 15% MTBE (methyl tertiary butyl ether), is acceptable.

This information was obtained from manufactures web sites and is a guide only. Please refer to your owners manual for correct fuel to use in your equipment.
Petrol Life in Vehicle Tanks
Unleaded E10 in Small Engines
Stihl E10 Ethanol Fuel Guidelines