I was running walk behinds for three years and had no problems with the cut. Last year mid season I bought a 48inch Lazer Z with a Kaw 19hp. I have had problems with the cut from the start. It leaves blades of grass uncut. I have tried different types of blades and speeds. The slower I go the cut gets better but I bought the rider so I could save time on my bigger lawns. Does anybody know what I can do?