Digital Speedo 90 HP Yamaha

Hi, I have a 1991 Yamaha 90 & wish to change the speed readout from km/h to knots. I know that this can be done because the 3 options come up when the ignition is first switched on. There is a "mode," & a "set" button at the bottom of the gauge. Also the same for the tachometer. Thanks heaps...

[boats.net]

The setting is on back of gauge, may have to remove it from dash to get to it.

Thanks

heaps for that my friend.