I have an Exmark Turf Ranger that has the Kohler engine on it. It has been serviced regularly, but our dealer has gone out of business. The motor has 1200 hrs exactly and is starting to get a rattle inside the motor. You can hear it when the motor decelerates quickly or accelerates quickly. I did a compression check and got 170psi on one side and 150psi on the other. Has anyone else had these problems? When I put in some STP oil treatment, things are a little quieter but still there.