I have an Ariens ztr model 1648 that is driving me insane. The mower was working fine and started giving me trouble all at once. I pulled it off the trailer and found that when I engaegd the PTO, the blades were having trouble turning. The motor is running strong and never seems to bog down or loose RPMs it's just the blades that lack power. I origianlly thought a belt was slipping but at this point I have replaced the deck belt, the deck to jack shaft belt, and the engine to jack shaft belt. I found an idler pulley that seemed to have bearing issues and replaced it thinking I had finally found the problem but still no dice. If I engage the blades over pavement, gravel, or VERY short grass, they will spin and slowly build up to speed and they will cut grass with limited efficiency. However, if the blades encounter any amount of thick grass or are put in even the slightest bind, they slow down to almost nothing. I have had the deck off of the mower and the blades spin smoothly with the belt off and everything seems to engage just fine without the deck attached. I am noticing a bit of a squeel with the deck removed, which seems to be coming from the PTO clutch itself. The PTO engages and disengages but it seems to be making a bit of a noise and I am wondering if it may be the source of my trouble. I have exhausted my limited knowledge and have no idea what is going on PLEASE HELP!!