2006-7 1028 Snapper Briggs and Straton 12.5 HP ?

My 2006 Snapper 1028 has developed a problem over the past two years by cutting out or just quitting when it became warm after running it for 30-40 minutes. One Snapper repair shop said it was those plastic parts that Snapper used in this models carberators. He also said that it was ethenol gas causing the problem as well. Another Snapper replaces said that the carberator had dirty gas and that the carberator would have to be cleaned and since it was that old, parts such a new needles etc would have to be replaced. I had already replaced the gas filter, drained and let the gas tank get dry inside and I vacuumed it out out. I strain all gass now. I service my mower very often and keep that air filter cleaned or replaced periodiocally. I even checked the carbertor bowl before I took it to the last repair firm. Brought it home and it has started doing the same thing after two uses. Can someone tell me what I might do to correct this problem? Should I use non ethanol gas? How about putting the new mix in the gas that supposed to eliminate what ever damaing effect ethonol gas has on motors like the B&S 12.5 motor on my Snapper. PLease advise
CNichols