Craftsman 15HP Stalls at higher Throttle Setting

I have a Craftsman 15HP riding mower 917. 256550. I just bought the mower and have no real history but I was told it always ran good. The Kohler engine CV15S Spec 41519 starts and runs great at half throttle and below but when I go above half throttle the engine will stall. I just changed spark plug, fuel filter, cleaned carb, and fresh gas and it does the same. I have attached some pictures and hopefully they show up but I am curious if there is a small governor spring that may be missing? I see the governor rod but curious if there is a small adjustment spring that is missing but I cannot find a diagram for certainty. Any help is greatly appreciated