[merc40ob]

I have a 1975 Id#676L51368 mariner outboard two stroke engine, the switch was damaged and I need to replace it, one problem the colors are a mystery. red, blue, brown,yellow, white, black, white, green. what do each of these go to, and the switch I have to replace it with has acc. batt. ign. and a lone connection in the middle.( I imagine that would be the ground?) where to do go now?

[Silvertip]

You first need to determine if the switch you have is for an outboard or an I/O (such as an automobile engine). If the switch is not a push to choke type you probably have the wrong switch.

Outboard switches have the following letters next to the terminals.

B = Battery. This is the red wire in the harness coming from the engine. It supplies 12 volts to the switch.

C = Choke: This is the connection to the choke solenoid or primer on the engine. Pushing in the key applies +12 volts to the "C" terminal and activates the choke or primer.

A = Accessory: This is the 12 volt connection for the gauges. Do not connect other accessories to this terminal as it is not designed for high current loads.

M = Magneto: This is the "kill" function for the engine. There should be two M terminals or one "I" and one "M". In the RUN position, these two terminals are disconnected and the engine will run. When you switch to OFF, these two terminals are connected together and that grounds the ignition to kill the engine.

S = Solenoid: This terminal feeds +12 volts to the starter solenoid when you turn the key to start.

I don't have a wiring diagram for that engine so I have no idea what the wire colors are in your harness. All of them can be identified with an ohm meter (provided you know how to use one).