Caveat emptor.
I'm sure I'm rubbing salt in an open wound, but, I have a problem (and I know it's mine) with the idea that it is a manufacturer's responsibility for an item which is admittedly +/- 7 months out of warranty. Seven days, that would be a different story. A half year out, while it hurts and it hurts real bad, that's the breaks. On these types of deals, you tend to lose more than you ever win - at least I do and that's the #1 reason I refuse to support 2nd hand purchases of consumer electronics.
There is quite a bit of truth in the "you get what you pay for" mantra. Unfortunately, someone got bit by this one. We make the choice to vote for quality or price. I'm a Wal-Mart, Home Depot, Lowe's, Big Lots junkie and I suffer for that choice - sometimes.
My recommendation on a Kohler, B&S and/or Tecumseh, find a local, reputable small engine shop for service. You want the support of your dealer, support them with the purchase of their retail product. Taking them the cut rate equipment from HD would be like taking a Ford Taurus to a Jaguar dealership and expecting the parent company (Ford Motor Company) to service a vehicle which is 5,000 miles out of warranty.