Re: outboard wont stop cranking
The solenoid is basically an electomagnetically activated high current switch--just like the tilt relays only much heavier duty.
Power is voltage times amperage. So since the starter motor is a 12 volt motor, it must draw a lot of amps to make sufficient power to turn over the engine.
The starter produces at least 1 horsepower at stall speed. That's a lot from a small motor. When the starter motor is energised, it instantaneously draws so much current (amps) that battery voltage drops to about 9 volts. I never measured it but I'll bet the amperage draw is at least 50 and probably closer to 100. That's why it heats up so fast.
You can not put this kind of power through an ignition switch without melting the wires and possibly the switch contacts. There would also be current loss by using such a long run of wire to the switch and back to the starter, and this amount of power is dangerous to have under the dashboard.
So a small current at 12 volts is sent from the switch to the small terminals on the solenoid. This energises an internal electromagnet (solenoid, from which the switch gets its name) which closes the silver or copper high current contacts inside the solenoid, delivering power directly from the battery to the starter. The size and material of the contacts make them able to handle such high current.
Of course, putting that much current through the contacts can cause them to spark. Occasionally, this sparking will weld them together and the solenoid will not open. More often, the sparking causes oxidation which insulates the contact surfaces and then the solenoid will close, but no current will flow.
Your solenoid contacts probably welded together, and the only way of stopping the starter was to remove the battery terminal--either positive or negative--preferably positive, in case there were redundant grounds which would cause wiring damage.
