Re: Testing Solenoids

[Buccaneer]

Frank, you explanation makes good sense. It’s nice to know "why" or
"how" something works instead of just being told "how" to do it!
I’m saving your explanation for my "archives".
Much appreciated!

quote FrankR:

Perhaps if I explain how they work it will make sense.

The two small studs on an OMC solenoid have an electro magnet pull-in coil between them. When you call for a start, electricity flows in one stud, through the coil and out the other stud to the mercury switch. As it flows through the coil, the voltage is reduced (just as if it were a resistor, which it is—a resistance.) So, the voltage being fed to the mercury switch is considerably less than 12V and the switch can handle it.

Enter the Ford solenoid. One of the two small studs is internally grounded, and electricity flows in one, through the coil, and to ground. The other small post serves an entirely different purpose, which is to feed a full 12V to the ignition coil, bypassing the coil’s resistor. That scheme gives higher voltage to the coil during starting, producing a stronger spark to the plugs.

So—if you use the Ford solenoid in an OMC, the full 12V meant for the ignition coil is fed to the mercury switch, and the switch can’t stand it and burns up.

Prepare to be boarded!