if I don't get 25 hours on the oil, I'll leave it in for multiple seasons. Last year, the simplicity might have gotten two hours use. This year less than an hour. There's no reason to change perfectly good oil. I don't use synthetic either. Total waste of money if it isn't used for it's intended purpose and that is extended oil change intervals and or extremely hot operating conditions. Nothing I own sees that kind of torture. As AA335 says, better off changing conventional oil when required than leaving well used synthetic in for ten years. The panic about condensation/acid build up in the oil is bovine feces. If water doesn't get into the crankcase from draining in from an exterior source, the amount of condensation will be insignificant, if at all. All one has to do if leaving oil in for more than one season is to run the engine until it reaches operating temperature and use it or let it stay running for a couple minutes. Air cooled engine oil temperatures far exceed the boiling point of water. In the very unlikely event that moisture has condensed in the crankcase, it will be cooked off.
Use a good quality 5W30 conventional oil and change it as per your manuals hourly use recommendation. The engine will probably outlast you.
This message was modified Feb 8, 2012 by borat
