Well it is going to be either FD750D (30+ different specs) if carbureted or a FD791D (36+ different specs) if DFI (Digital Fuel Injected). Can't narrow it any further on this end.
This is why I record every piece of equipment's engine's model, spec, and serial when I first received the unit in for repairs. This has been a big help maintaining a customer's machine as those model, spec, serial number tags do disappear in use.