I've had an ever-worsening high idle problem for several weeks.
Nate Bandit finally diagnossed it: a pre-carb air leak.
"Fuel" is actually Air + Gas + Oil
Sure enough, I had traces of oil underneath my air cleaner. So, a screw, a crack, a seal or something is working it's way loose causing more and more air in -- thus a leaner mix and thus a higher idle.
Damn, I kinda hate it when he's right -- But Thanx Nate.