My mower has a motivational issue

[bmartinson]

I have a new Troy-Built mower with Honda engine that I bought just last fall. Only used it a half-dozen times, then out of ignorance stored it for the winter with E-10 fuel still in the tank. This spring it worked just fine once or twice, then this past week it failed. It will start up and run for about 60 seconds, then die; after that, I can't start it at all until several hours later or the next day, where it will maybe run for less than a minute again. I drained the fuel, bought new gas, added a dash of STP, checked the filter, changed the spark plug -- still no go. Incidentally, I also noticed that while cranking, my choke returns to the initial position more slowly than it used to.

Is there anything else I can try before I pay somebody half the price of the mower to fix it for me? This has been a great mower and I'm just sick at the thought that maybe I've killed it.

Thanks,

-Bill