tach wiring

[smegargel]

I am trying to wire a fuel management meter into my boat with twin 225 yamahas '02 models. I need to know which green wire on the back of the tach is the one I need to wire to the fuel management. Is it the green and red or the green and white?

Thanks

[boats.net]

Here is a diagram
FMM_Wiring.pdf

[tuckerboy]

Would you by any chance have a diagram for connecting the key switch to a multi tach?
daddy