High rpm should be 3600 or close to it. I try to get the gov set so it will recover to over 3500 once the PTO is engaged and the mower or snowthrower is up to speed. Running an air cooled engine at less that full RPM under a load for any length of time is a good way to overheat them and burn up the rings, causing premature oil burning and smoking. Idle I normaly set by ear and is the lowest she will run without stalling, loading up or cutting out when I come off of idle to full power quickly, called a snap test. More than likely the carb has plugged up jets and grime from our poor excuse of fuel we call gas. The ethanol in the fuel seperates from the gas portion and is very corrosive to the carb parts, gums up the jets with a brown goo that even our best clearers and soaker can will hardly do anything with. If my 110 will sit for any length of time, I shut off the fuel on the bottom of the tank, and run her still she dies. Mike