1986 225hp instruments to Nmea

[Jabiru76]

Hi
Just installing a Lowrance HD10. I have a 1986 225hp with guages that look like the round command link instruments however wiring at rear is not the plugs as shown on current manuals (simply wiring going into instrument and a pitot tube). There is an unused multi pin plug coming from a short lead at the rear of the speed /fuel gauge.
Is there an installation manual for this version that I can access online?
Is there any way of linking the instruments to my HD10 via NMEA ?

Thanks
Brian

[rodbolt17]

nothing on an 86 yamaha is NEMA compatible.
some of the later speedometers can accept input data from a GPS but they dont transmit to a GPS.