Running Honda EU generators re-jetted at high altitudes.

I don't have a horse in this race, I don't own either, but my snowmobile partner has a Yamaha gen 2k or whatever it is. We have used it in January at 10,400 ft in the Snowy Mtns with no issues at all. We use it to power his trailer as a mobile work shop for when we break stuff. His 42k RV furnace also works great at this exact altitude. I forget what brand furnace it is.