Small Engines (Lawn Mowers, etc.): Safety switches, safety switches, battery terminal

Question
I read where you told a couple of guys to test there safety switches by bypassing them with a wire. How do you do this? I've replaced my battery, solenoid, ignition, circuit breaker and spark plug but I still get nothing when I turn the key. I'm suspecting one of the safety switches may be bad or out of adjustment. As you may have noticed I'm not to good with trouble shooting. Thank you for any help you may be able to offer!!! My tractor is a 1986 montgomery ward 11hp model# TMO-33917A    Serial# 91-001-0170

Answer
Hi Will,

Some switches are normally open, some are normally closed.  This means that a switch may need to connect or disconnect the wire, to allow the ignition to operate.  If it is supposed to be open or not complete the circuit, you can remove a wire from it's terminal, which will do the same thing that the switch does.  If it is supposed to be closed, you need to attach a wire from one terminal of the switch to the other terminal.  

You don't mention the starter.  To test that, follow my NO Crank proceedure below.

Let me know how you make out.
Michael

I would check the starter first.  Jump the positive battery terminal to the starter and it should crank over. If so, skip to step 2.
If not, jump from a battery that you know is good, from a car.  If still nothing, the starter is bad.  If good, then the mower battery is weak.  

Step 2.
If the starter and battery are good, you will need to trace the entire circuit from the starter to the battery.   The solenoid, switches the battery power to the starter, when power from the key switch is sent to the small terminal on the solenoid. To test the solenoid, first make sure that you have power at its large terminal which comes from the battery. Then jump power from that terminal or the battery positive post, to its small terminal. You should hear a click and the other large terminal that feeds the starter should be energized. If not, then the solenoid is bad. If good, then continue tracing the power through the key switch to the battery until you find the break in the power path.   All testing can be done with a 12 volt light or a voltmeter.  Most equipment has safety switches in  the seat and on the blade engagement lever. Check them by temporarily bypassing with a small jumper wire.