Belt Tension Mower Deck Drive Belt

I cannot find the correct tension for the Mower Deck Drive Belt on my Ferris Evolution Model 5900779 with 48" Deck EVKAV2748

I have just replaced the mower deck drive belt because the original belt would not stay in the pulley groove properly. The belt would turn 90 degrees which would make the belt tension assembly vibrate rapidly. I have just installed the new belt (no small task for an old fat guy) and broke in the belt following the owner's manual instructions. I mowed for about...

Belt Tension Mower Deck Drive Belt