I have been using the gasoline with 10% ethanol that we have here in Texas for about three or four years now and haven't had any problems at all with my Walbro carbs. I was told that Walbro carbs are OK for use with the standard pump fuels that have some ethanol for emissions reasons. It makes sense because most states now have ethanol in their gasoline and that fuel is being used in weedwhackers, chain saws, blowers, etc. without trouble.