I did not run it afterwards. When I cut the wire the engine stopped. This morning I wired it back to the way it was before. Line going to engine power on switch at the helm to battery sense terminal and the sense wire going to the opposite side battery. Crazy, I know, just trying to go back to what was working. I decided to see if the engine power on/off switch at the helm was was perhaps bad. I powered up the engines on the main panel. Port engine switch works fine. Turn on lights up MTU gauge. Start engine. Turn off Port switch engine turns off. STBD on/off switch was not having any effect on the STBD engine panel. I pulled the switch and tried pulling out the blade connections, one, the other and both. So, I think the switch is not my issue. Wondering if the new alternator is energizing the battery sense terminal? No strap on the alternator. I know I should not turn off the battery switch while the engine is running. Is it safe to power off the ignition circuits at the main panel while it is running?
Your question got me thinking. I disconnected the wire I cut. Engine now starts, runs and is charging at 14.5v. And it turns off when I turn the switch off. How or why IDK. Port alternator seems to not be charging. Helm shows 13.1v. Thinking I’ll disconnect the same wire from it. Some day I’m going to draw a diagram of how this boat is wired…