Ignition switches are different between OBs and IOs. Unless you get an exact replacement switch, the wires will need to go to different terminals. You need to be concerned with 3 different connections: 1) 12 volts into the switch 2) 12 volts out of the switch going to the gauges and engine ignition and 3) Momentary This is where you twist the key and you get a momentary 12 volts to activate the starter solenoid. If your boat has Fuel Injection and such the ignition switch may have more connections.
The new switch should have a wiring diagram to identify the mentioned connections. The boat wiring diagram should identify that ? color of wire for the 12 volts coming from the battery, the starter wire etc The picture shows the complex switch. Some boats still use the older 3 wire connection
Here's another post regarding OBs
http://forums.iboats.com/showthread.php?t=373277
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Pay attention to the B, S and A connections below.... If you have an IO
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