Wiring diagram to solve problem on Mercury Outboard

[craige1982]

Hi all. I have a 40HP Mercury Outboard (approx 98 model) which I have just put on a boat with a Quicksilver control box, and I have a problem where it will start fine however it will not turn off when I turn the key off. The only way to stop it is pull the leads from the spark plug. There is a blk/yel wire which when connected will stop sparks getting to the plugs, howver this will prevent the sparks weather the key is on or off. Does anyone have a wiring diagram for the 40HP outboard, or the quicksilver control box? Any help would be greatly appreciated. Thanks

[cbcrawford]

You should post this in mercs . . . but I'd avoid asking for the diagram, just ask for help. Some of the moderators (rightly) get upset when you ask for material that is obtained commercialy.First thing you should buy with any boat is a manual for the outboard, it'll have the diagrams for the controls in it.CC

[Pickels]

Sounds like you have power to the boat 100% of the time - and the only thing your key switch is doing is engaging the starter.Easy to test this if your motor has a rope pull starter on it. When the motor is not running and with the key removed - pull the rope starter and see if it will run. If it does -- it will be simple to find out whether you have a defective switch (use a volt/ohm meter).

[joblo33]

BTW, unplugging the plug wires while running will wreck your coils. Use the choke to kill it in that situation.Eric

[TELMANMN]

Here in the states I would go to a public library and get a schematic. I do not know if that is available down under. I have a 98 merc. book but it is up at my cabin and I will not be up there till next week. As previous post said, just choke it too quite or pull gas line.

[Moody Blue]

Are you able to stop the motor using the kill switch ? If not, then the problem is likely that you have a bad ground in the kill circuit within the control box.

[JohnRuff]

Did you find the answer?