Small Engines (Lawn Mowers, etc.): Riding lawn mower wont start, plug fuse, riding lawn mower

Question
I have a yard machine,I think it's a 1998 model.It has a 12.5 Tecumseh engine model OHV125.Last year when I tried to last mow my yard it started to crank but would not and backfired once and then would do nothing but a clicking noise.I tried to start it two weeks ago and it would only make a clicking noise again.So I replaced the solenoid,battery,spark plug,fuse,and air filter.Then it still would not start and no longer even made the clicking noise.So I then replaced the starter.It still will not start or anything. No noise at all.What could it be?  

Answer
Hi Chuck,

It could be the key switch, safety switch or wiring.  Following, is my general "No crank" proceedure.  Maybe it will help:

I would check the starter first.  Jump the positive battery terminal to the starter and it should crank over.  If not, the starter is bad.  If good, then 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.

Let me know how you make out,
Michael