Does anyone know what parts it takes (persumably carb parts) to convert a Kawi 23hp (FH680V) to a 25hp (FH721V). They're the same engine, but there's a couple changes to it to get the extra hp. I'd like to buy the parts for my Hustler Z and I can't find a deal that knows. Most don't even write me back. It just can't be that hard. I can't even get a number for Kawi.