I just had my 16 hp B&S 307333-0332-01 engine professionally rebuilt. (It was removed from my tractor and shipped out out-of-state for repair.) I am having trouble getting the throttle/governor adjusted. When I first started it, the engine would barely rise above idle when using the throttle control. However, I could manually open the carburetor butterfly and the engine speed would rise appropriately. How do I fix this and adjust the governor?