Hi All I am rewiring a twin engine boat. It is a 30 ft speed boat with twin Mercedes diesels. I have replaced all of the gauges and fitted a gps speedo. I am struggling to find the correct way to wire the fuel gauge and the speedo. I have separate ignition switches for each engine. The gauges (rev counter, oil, water and temperature) are also separate for each engine. Can anyone tell me the correct way to connect the speedo and the fuel gauge?

the speedo and fuel gauge connections don't have anything to do with the motors, other than getting turned on when you turn the key or turn on your electronics if they are switched separately. The gps speedo should come with wiring instructions and you will need a GPS antenna. The fuel gauges should have some or all of the following connections negative, switched positive, illumination (positive when nav lights are on), and sending unit connection.

Tell us more about the MB diesels and your setup some pics would be great!

Hi. Mercedes car engines standard om606.962 . had the injected pumps built in Sweden by a diesel genius have a look at my link on u tube .
https://www.youtube.com/watch?v=-c7oDGgBsIE

http://www.offshoreonly.com/forums/g...lp-wiring.html