I just got off the water, and trying to remember about the MIL. Yes, I was getting a beep, and the light was slow flashing like the vid. Maybe once per second! I actually bought the boat from a buddy who only used it twice after he bought it used. He replaced the thermostat, and didn’t realize the bolts were different lengths. So when I got it water was pouring over the plugs/wires running rough, and I was getting a voltage code (bad ground wire) and the crazy O2 sensor. Fixed water leak, replaced plugs, repaired ground wire. Still was getting the O2 code. Ran fuel cleaner hard, then came back reset codes again, and all is well other than the stumble at idle. Gonna order new injectors as they made my Yamaha run a hundred times better. Now the light comes on with key, and two short beeps, then when motor starts all lights go off! I found a diagnostic booklet on line, but can’t link it here? Send me an email, and I’ll try to forward it to you. I think it’s exactly what you need to move forward. I’ll remove my email as soon as you contact me. Hopefully it will be of great help to you.