My 266xp recently started revving high then bogging while cutting. I took it to my local dealer and he adjusted the carb and it ran for about ten minutes before it started bogging again only this time it didnt rev high before bogging. I took it back and he checked the tank vent and verified that it was working so he changed the spark plug and fuel filter. That seemed to make it better but he told me that I needed a muffler because it wasnt baffling correctly and that I needed a carb because the high set screw was adjusted all the way in and it was still running. I was told by another mechanic that the carb could possibly be dumping fuel internally and that he would rebuild the carb since it has never been done since I bought it new. Has anyone encountered this issue and if so what fixed it. I dont mind replacing the carb if I have to but if it can be fixed with a rebuild I would rather go that route. Thanks!