While traveling at almost WOT, my outboard motor suddenly died. It’s a 75 HP Mariner late 80s or early 90s model, you can see the cowling in pic. When trying to start it back up, I noticed something sounded different as if it was a bit higher pitched and faster while starting, and could never get the motor to fire back up. Primer bulb is firm and tested it out to make sure fuel is being delivered. When troubleshooting I took out all 3 spark plugs and they appeared to be in good shape. Then I noticed the two yellow wires you see in the pic have turned to an almost black color which is obviously not how they should look, with good looking connectors right beside on the green/white wires. Then, I looked and my kill switch is a flip style with run or off position. I flipped it up and down a few times and still wouldn’t fully fire up, only continue to turn over continuously. I know the kill switch wire is black and yellow, so I decided to pull back the rubber cover and remove it just to test, and to my surprise the motor fired up, and even when turning the key to the off position and fully taking it out, the motor would not turn off. So I went back and reconnected the KS wire, the motor immediately turned off. I believe the issue is with the kill switch, but the thing is I have removed the wire and tried to start the motor again with no success of it firing up once more. The motor continuously ran like it always does the first time but now it won’t start up even with KS wire removed. I am completely confused and would love some insight from someone who has possibly worked on these or similar mercury motors, thanks!