Yamaha tachometer. 6YBT-11

[robanfield]

I have been trying off and on to get this working correctly for a long time, but without success. Engine YCOP etc all work, tacho starts up but no revs no engine hours etc. I only get trim/tilt and image of boat / small dash in centre. I think I have installed correctly. There is only a 4 pin plug on back of tacho, no extra wires or dip switches. Tacho is plugged into hub/device socket. Yamaha 50hp l/s 2016. Everything was bought brand new and only used 4 times owing to illnes. Please have a look at pictures. I have tried to follow wiring diagrams all to no avail. Should there be another cable from engine to controls, I only have 1 large multi cable plugged into engine
I would really appreciate any help.
Best regards to all,
Rob