Hmmm... Looks like I was WRONG! Doing a little more research... My engine is a FH601V-CS13. When I compare the FH680V-DS22 to the FH680V-CS13, I see the DS22 has a round bowl at the bottom of the carburetor and a circular float. The CS13 has a rectangle bowl and the float is butterfly shape. And the throttle shafts seem to have different part numbers and prices. I guess if we just grind the throttle we don't need figure out which parts to buy! I'm currently waiting for "my guy" to get back from vacation so he can grind this for me. Maybe the FS15-R means "must buy parts from John Deere"! Incidentally, I bought the oil cooler and installed that without a whole of effort! If nothing else, it should run a little cooler.