I have a Cub Cadet with a 25hp Kawasaki FV721V engine. This machine has never given me any major issues since I've owned it for five years. It has approx 125 hrs on it. Recently, when I cut thicker grass the engine bogs down and stutters so bad that it almost shuts down completely. I have to back up to take the load off and the engine has to catch up to relieve itself. It also started to do this when I made hard turns in the yard. Any kind of load makes the engine want to stall. Even sometime when going up a hill. I was thinking it might be a bad coil?? Can someone explain how to test the coil and what the readings should be?? I changed the in-line fuel filter and blew out the air filter but was no help. Any suggestions would be greatly appreciated.