Mowing RCK60B questions

[Scrounger]

I have an RCK 60B that has started to make sporadic noises that sound like a harmonic vibration. It stops quickly and when it lasts longer just turning the deck on and off seems to stop it.

Could this be an out of balance blade or could the belt be loose. I'm not sure what the adjustments are for the belt on the deck.

 

[OrangeRidge]

I'm assuming the belt is tight ? If the blades are intact and looking good ,
then check the top bolts holding the spindles to the deck .