I have a 50" Troybilt ZT with the Kohler Courage 25 horse motor.the [roblem I am having is whenever I mow down or up a small incline every once in awhile it will bog down and spit out a big cloud of white smoke like it dumped oil in the exhaust.Any idea why this does this and how to fix?I noticed it did this when I made a sharp trun this weekend once as well,,