sst18 vibrates at higher rpm

[c52fm306]

I have a John deer sst18. I just had a new short block or in it. At idle it is perfect and runs beautiful but as soon as you idle it up there is a severe vibration. It almost seems to smooth out a little when blades are engaged. We replaced the traction belt and cleaned all of the pulleys but it still happens. Amy ideas?

 

[Rivets]

Start to diagnosis by removing all pulleys and see if the vibration is still there. If it is, you know you have an engine problem. No vibration, install one part at a time. Pulley first no belt, add belt, etc. When you start to see vibration you narrow down the cause.