We're going to give it a go at cleaning the carb ourselves this weekend when we're down at the boat. Hopefully giving the carb a good clean will take care of it.
We also found a place to get ethanol-free gas approx. 60 miles from here. Frankly, if that's what's causing the problem we will gladly make that drive with a few 10-gallon portable tanks to stock up!
Your motor is rated at 1 gallon per hour fuel burn at 5500 rpm. That said you can run at full throttle for about 3 hours on a tank of gas. In reality you will not be running nearly that much gas through it. I wouldn't stock up on a bunch of bulk fuel unless you have some other gasoline sucking equipment to use it in.