I have an ST .90 bought it spring of 07 I would guess I have about ten gallons through it. I'm horrible at tuning an engine. Fortuately, I have a club memeber that is good. it seems like we adjust the low end in the spring then again in the middle of winter. We fly every Saturday if it not raining, or snowing, and a few times in the snow. Otherwsie a click here or there on the top end at the begining of the day, and I'm ready to fly, I also have two OS it the same story with those engines. I would buy another ST if I need an engine without a second thought.