Yes after some research I discovered it was a bonding wire. I suppose it should have black insulation over it like the other one that is connected. I can't find an O ring on a bolt it should be attached to. If someone could post a pic of one that is attached that would be great.
What outboard do you have? With my pontoon there is a wiring harness coming from the motor for the gauges. And a inline 50 amp fuse from the battery for power for the lights and gauges. The wiring is color coded by the motor brand as someone posted above.
