I have a Kaw 12.5/Exmark Metro carb prob. I have had this mower three seasons now, and it has now started to cut in and out. After prolonged use it is more noticeable. If it dies out out, it can be restarted with no prob. I have changed the fuel filter, and have even taken the air filter off to see if that was the prob. I have cleaned the carb out. What else? Does the carb need to be rebuilt? I only have a few more weeks of mowing and I'm so aggrivated!!!!