Definately The higher Octane.Setting aside Joes post for 1 min...The higher the rating the cleaner the burn.Since a two stroke has oil as well to consider in the combustion process it needs to be burnt more efficiently.The low octane fuels tend to foul and build up carbon much more quickly.There are cases for and against.Most GOOD manufacturers design their engines to run on certain fuel types and ratios.When the introduction of unleaded crossed over many years back the fuel octane for "Super" was also around 95 octane and the prefered choice by mower makers.
Now back to what joe was saying.This is true..So VERY true...A few years back when the big hoo ha was on about dishonest fuel sellers putting Ethanol in their fuel their was no screening.Its not as simple as just adding ethanol to fuel..It has to have additives one being ANTI moisture agents.In a 12 month period I saw a massive increase in failing fuel systems,severely rusted tanks totally corroded and rusted fuel line and injector rails.Whole systems that were destroyed completely by the use of shall we say unlicensed ETHANOL...Now things are different and car manufacturers cater for the use of ethanol much better.But the people were burned already.This is in my opinion why ethanol still isnt trusted completely.I do not know if mower manufacturers have recommended the use of ethanol fuels,so in Joes case maybee they didnt factor in the damage it could do to other components and why his fuel line melted:)
