Bunton howls when blades disengaged
I have an older (circa 1991) Bunton 36" hydro with a Briggs Vanguard 16 HP motor. I bought this project as a fixer-upper to mow about an acre of land that I own. I replaced all of the deck belts along with one spindle and a deck pulley this spring. I am having a problem with the main deck PTO belt catching on the driven pulley when the mower deck is disengaged. It howls loudly, and I am afraid that I am going to smoke the belt. It seems to get worse after the belt heats up when the mower has been run a while. I set the clearance on the belt guides as specified in the Bunton manual. I have tried several different positions on the release lever that engages the idler pulley, and I have tried different belt tensions, but nothing seems to work. Does anyone know what the specs are for belt tension on this mower? I guess I could increase the clearance on the belt guides, but I am afraid that the belt will slip off the pulley when disengaged.
Any advice is greatly appreciated.
Thanks in advance!