While adding a 3rd Lowrance MFD to my system, I found out that I have 2 NMEA networks. The original network includes
two HDSGen 3's, a Point 1, and a Motorguide Xi5 Gateway connection. When I repowered with a ETEC 150HO, the dealer installed Evinrude Icon Pro gauges, and apparently created a second network, which now includes a HDS Live, a NMEA temp sensor, and a Evinrude engine interface, as well as the Icon gauges.. I connecting the 2 systems so that I have access to all NMEA devices on all 3 Lowrance displays. Each network has it's own power supply. Can I keep both, or do I have to remove 1? If I can keep both, do they need a common ground? Thanks for any help you can offer.