Hello I am new here and I just bought anew oliver super 55. There are acouple issues. 
First, it idles high. I can adjust it down but it goes back up. I had to connect a spring to the arm on the carb to keep it from creeping  back up

Second and scary issue is, there is a grinding noise when the tractor is in reverse. It happens mostly in r2 especially uphill. Thank you  in advance