Bought this D140 in April 2013 new. It has never cut well. My yard is mixed grass and weeds from dandelion to coastal Bermuda. It never fails that as I am cutting it will leave standing patches, sometime small strips. I am constantly double cutting and overlapping more than I think necessary. I have the predator blades on now which are supposed to be the best. Even sharpened them beforehand. They cut good once then back to the same old cut. Have tried different deck heights with not much luck. I try to cut at a moderate ground speed and WOT. I have found if I slow the ground speed down to a crawl, literally, then it cuts much better. But I have a little under 2 ac. and that dramatically increases my time cutting. Have a friend with and older model equivalent that is 48in deck also, La model I think, says his cuts the same way. Here is what we were told. The commercial zero turn models use the same deck but the blade tip speed is around 2000 rpm higher. They seem to cut much better at full speed. Is there any truth to this being the difference? Can the pto/pulley be used from a zero turn be used on a D140 model to increase blade speed?. Or does anyone know any tricks that would help these mowers give a better cut?