Model 13RN772G029
Serial: 1B118B10093
I did new belts and after noticed a kind of rhythmic, intermittent vibration when the blades are engaged. Don't know if it was there before because the owner mows with headphones. I did mention it to him and had him test it out and he then noticed it. The point being, I don't know if it was there before or not but I guess that's kind of irrelevant at this point.
I observed the idler arm vibrating, bouncing up and down a bit in 2-3 second intervals. The blades are new, spindles in good condition, pulleys aren't wonderful but there's no play in them. But I can move the idler arm up and down quite a bit. It seems that the shoulder spacer, number 37 on the diagram, is bottoming out before the arm can seat flat on the mount attached to the deck. This is resulting in some play there.
My question: Should this arm have a little play and could this just be a bad pulley causing drag and thus the vibration? Or should these parts seat up nice and tight? Meaning the arm to the mount that it pivots on.
On a side but related note, I'm not seeing a part on the deck diagram. It's a spacer about 1.5 inches long that goes between the top part of the mount and the deck. The bolt for the pulley slides through it and then a nut connects under the deck. It's located where number 48 is on the diagram, which they show as a bolt.
Model parts diagram:
https://www.mtdparts.com/en_US/prior-year-models/yard-machines-riding-lawn-mower-model-13rn772g029/13RN772G029.html?d=t#/MTD_Merged_Data_Staging/13RN772G029_(2008)/Deck_42_Inch/509cb6bf-ebc9-4c39-95ef-4911fefd7afb/78547bc6-ee80-4af4-a02c-fd660ee812ea/y
Thank you. I should add that this machine takes a beating. As stated, the owner cannot hear what's going on when mowing but being that I live across the street...I hear it all...the rocks, branches, and even the occasional curb. It's horrifying.