FH580V High Idle Adjustment Trouble

Hi Guys,
 
I'm working on a 19HP Kawasaki fh580v on a bob-cat fast cat zero turn. I am in the process of setting the low and high idle speed adjustments. Low speed adjustment went fine, adjusted at the carb and at the control plate set screw per the service manual. The high side is where I'm having the issue. It calls for turning the throttle control all the way up and then manipulating the control bracket on the back of the engine up and down to set high idle speed. The trouble with that is, I don't get more than halfway through raising the throttle control and the rpms shoot up well over the high idle spec. Adjusting the bracket isn't enough to compensate for how over-revved the engine is at full throttle. There's a brand new governor spring and I did a full adjustment of the governor assembly (using the procedure recommended in the service manual) before attempting the high/low adjustments. Let me know if anyone has an idea of what could be causing this issue. Thanks!