Small Engines (Lawn Mowers, etc.): Jumpering Switches, briggs and stratton, jumper wires

Question
Hello. Please excuse my ignorance...I am a bit new to this. I have a 1990 18 hp MTD Ranch King lawn mower. Model: 140-849H205. Briggs and Stratton Engine. It will not crank...no clicks, no noise at all. I have power going to the ignition switch but can't find anything beyond that. I keep reading about "jumpering" the safety switches to see if one of them is faulty. Now the ignorant part...how exactly do you jumper the safety switches (clutch, PTO, Reverse, Seat, etc.)? The clutch switch has 4 wires running into it...2 red and 2 yellow.

There is some rust also on a few of the terminals, including the switches and solenoid. Is there a good cleaning solution or solvent to use in removing it?

Any help you can give along with any other ideas of what to check would be greatly appreciated.

Answer
BUY A TEST LIGHT!!!
Put the clamp on the negative battery post and use the probe to test the switches. Turn the key to start and follow the voltage though the switches.
If you don't have a test light get one.
It is actually illegal for a registered tech to tell you how to use jumper wires, up to 20,000.00 fine for first offense. That doesn't even include the civil liability when you cut your fingers off or worse, drive over the wife's Begonias.
Good Luck

Don't punish me by giving me a poor rating because of your lack of knowledge and my legal restrictions. Buy the test light ( about 8.00 at your local parts store), it will be easy to use and will give you fool proof results. Try it and then see what you think of my advice.