Wish I had all the answers but I don't so here I am...lol Cutting a lawn today (bi weekly account) the grass is a little tall so I leave the deck all the way up like I have done previously - side discharge and I lose power cutting the grass in sections where the grass is taller. Don't get me wrong is was a little tall but wouldn't think it was tall enough to lose that much power where it almost shuts down. Three new blades, inside the deck is clean, just replaced two of the three housing and spindles shafts...because the third new housing had bad bearings so I have to send it back. So I had to put the old one back on. Belt Is in good shape and is tight. Anyone have any ideas? Could it be a bent pulley? I was told by someone that the tension pulley had bad bearings...but have the time this person doesn't know what he is talking about. Any suggestions would be much appreciated.