All you have to do to make sure a modern engine doesn't gum up is to not leave fuel in the carburetor while it's in storage. The simplest way to do this is to either drain the carburetor (there's usually a screw that can be removed for this) or stop the engine by closing off the fuel supply (some have a valve for this) and letting it run until it stalls. Doing this, I've not had any issues burning 10% Ethanol fuel.
Engines: lawn mower (12 year old Toro), brush hog (6 year old Husqvarna), 2 chainsaws (6 year old Stihl, 3 year old Husqvarna), weed whacker (6 year old Stihl), Kipor generator (5 years old), big split/phase cheap Chinese generator (2 years old).
There are no Yamahas in my stable though. If they really do have issues with E10 fuel, that would be cause enough to avoid them! (I wouldn't want to have to hunt around or spend my vacation driving a long ways just to get a special fuel.)