48” deck has some pretty strong vibrations

[kick 59]

As stated this deck vibrates and sounds like a jet turbine.  I recently just purchased a 416-8 (Kohler m16) with this later model deck (78361) attached.   I haven’t removed the deck yet but during the purchase i checked the spindles (no movement).  Belts look ok from what I could see with the shrouds on.  No visible damage to deck.  I also loosened up the mule drive and spun the spindles.  Everything seems normal and overall the deck is in excellent condition.  I will remove the deck and belt shrouds and do a more thorough inspection.  Any ideas much appreciated.  

[JAinVA 4,619]

If you don't find anything out of kilter with the checks you propose it may be unbalanced blades.The tip speed on the 48" blades is much higher than a 42" and balance is more critical.I would look in to that area.

Edited August 21, 2018 by JAinVA

[Dirtdog524 61]

I would start with the blades. Remove and stack the three together. If one is bent , it will be obvious to you. They should stack up without any gaps etc between the blades. Sharpen them and balance. If this does not fix your vibration then you may want to look further into whether you have a bad bearing in one of the spindles or if a pulley is not running true . Lastly, look at the mule drive and make sure that the two bearings are good. 

[peter lena 8,582]

found that as the pulleys wear , the inner side of the pulleys get thin, and pick up a vibration that cannot be stopped due to poor fitting belt. had this on a recent deck I picked up, typically its the center drive pulley , replaced with new pulley, smooth and quiet. pete

[kick 59]

Removed the deck and belt. Looks like bearings and possibly one outside shaft are in order.  I need to pull the spindles and check runout.