My mower is ventrac 4500 with rough cut deck. I am having issue with the belt from the PTO to the drive shaft pulley.
Belt is tight while machine is parked but throws belt off when mower blades engage. Need suggestions.
Do you have other powered attachments? Are they working ok? If so I'd take a look at the pulley on the driveshaft ,make sure it didn't loosen and move or was adjusted wrong from factory...they should line up pretty evenly,they don't have to be perfectly,in alaignment because the position changes as the hitch moves up and down somewhat .If that checks out I'd make sure your belt is tight enough a loose belt wil not only slip but jumps off the pulley easier.If you haven't used any other powered attachments successfully I would take a look at the engine to pto belt condition and the pto double pulley setup make sure the lower pulley isn't damaged from hitting something when there was no powered attachments on.Also make sure double idler pulley mounting bolt is tight and sliding linkage for idler is tight .