1982 mercury 50hp wont shut off help.

Ive got a older mercury outboard 50hp 4 cyl. Starts and runs great. Will not shut down with key. Just replaced starter and switchbox module. When i turn the key off it still runs. I pull the plug wires to shut it down it has no change when i pull the top 2 plug wires off but will shut down if i pull one of the bottom plug wires off. So its shutting down the top 2 cylinders and keeps running on the botton 2.
I pulled the black and yellow wire off the mercury kill switch and grounded it and still does the same thing. So im thinking my problem is in the engine area and not the key switch.

Try grounding that wire at the engine, probably a problem at that connection in the harness, or not an effective ground at your dash/control switch where you tried to ground it.

I did ground the black and yellow wire at the engine

The switch is working but its only shutting down 2 of the 4 cylinders.

Okay, I GET IT. That's gonna need advice from a better tech than me. Maybe Racer, Bullet, Jeff, or Gator. Joe is mostly Johnson Evinrude.

My guess is that you still have a problem with your switch box. Since pulling the top two plug wires and that doesn't change the way the motor runs, it would tell me that your motor is only running on two cylinders (the bottom 2). The fact that you said that you grounded the yellow/black wire at the switch box to the engine block and it didn't stop is another indication that the switch box is toast. I don't know where you got your replacement switch box (was it new?) but I would surely talk to them.

FishinLite said:

My guess is that you still have a problem with your switch box. Since pulling the top two plug wires and that doesn't change the way the motor runs, it would tell me that your motor is only running on two cylinders (the bottom 2). The fact that you said that you grounded the yellow/black wire at the switch box to the engine block and it didn't stop is another indication that the switch box is toast. I don't know where you got your replacement switch box (was it new?) but I would surely talk to them.

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I got it new from amazon. Its most likely just a cheap chinese brand. I ordered a CDI brand and will see if that helps. Thanks

Was there a feedback on the seller, or a rating for the product? I have purchased similar electronic components without problems. It will be interesting to see what you find here.