Just got my 2020, cutting my grass here in northern Ohio at 3 1/2 inches, after cutting I let it cool for 20 minutes, then use my deck washout port for 3 minutes at lowest level on level blacktop driveway, with the blade cutting, guide a bit of grass comes out, but it still leaves in quite a bit, they say to use the washout port, after using I disconnect the hose and continue to keep the blade going for 5 minutes, getting discouragedastowhy it is not cleaning all the grass out. Today jacked up the mower, did not disconnect the spark plugs because I know that if you do that over a period of times it will give you problems, seams like I am wasting my time, would like advice on this.