Engine Scag 61V wildcat kohler eng oil level

I believe I am going to have to have work done on this 27 hp Kohler engine soon. It seems to be blowing oil out through exhaust. I have to refill it some, every time i use it lately. It also is running slightly rough, except when I crank the rpm's up. Can someone give me a rough estimate of what the cost is to have the work done on the engine? Thanks

Engine Scag 61V wildcat kohler eng oil level