Yamaha digital Tachs

[puddmurphy]

I just bought a new boat and all new gauges,electrical harness, control boxes, digal tach, speedometer. I'm using my older 94 C55HP Yamaha's.
The tachs are not working and I'm wondering if anyone can give me some input. The older analog tachs worked fine.
Is the harness on the engines compatible with these tachs?

[rodbolt17]

depends on what you bought.
can you post some pictures or at least part numbers?
pictures would help me better.