Like everything Stihl, even finding basics (fuel/air filters, plugs) is a challenge. They won't provide a parts list so unless you obsessively record the part numbers (and can find them again) you're back to Googling any time you want a replacement. They also don't reply to emailed questions. From Amazon I have about a 50% success rate of aftermarket parts fitting: I have a quart ziplock full of new fuel filters that don't fit the Stihl fuel lines and another with air filters that are the wrong shape. Obviously I have to get organized and write things down for each tool once I find a part that does fit . . .
On the KM and the blower I did try tinkering with the adjustment screws. Nothing conclusive and they still wouldn't run high. I used these instructions more or less, translated to non-chainsaws:
Anyway, I'm on vacation (term used loosely) this week and wanted to blow the driveway to get ready for new gravel, string trim about a quarter-acre of weeds, and cut down two trees. I wouldn't say that's especially ambitious for a guy with all the right tools! All tools were working fine a week earlier as I said. But just when I needed them they crapped out. Experience with the dealer tells me it will take 2 weeks for anything.
So I gave up last night and tried some MIB I had sitting in the garage for emergencies. It was either that or the rental store. I have to report that I don't think "No MIB doesn't work" is the right answer. After idling the tools for awhile with MIB in the fuel last night then letting them sit overnight, all three tools are revving up superbly this morning. I used the blower for an hour this morning and it sounds like new and it got even better as I worked.
Maybe the TruFuel was the problem, not sure. I'll consider switching to fresh REC-90 and one of the premium oils suggested above. Which is almost unworkable logistically because mixing less than a gallon is dicey but a gallon is too much for a homeowner type like me to use in a month.