I purchase a Honda 21in mulching mower and am having trouble with stray grass. Even with sharp blades and mowing at a very slow speed, some grass is just matted down or simply is standing up after I cut. I also notice that when I turn 180 degrees, I have to overlap my pattern greatly to get uncut on the edge where the tire went over. Any one know if this is common on the honda quadracut mowers? Is there anything I can to to fix this problem?