First the clicking sound is the fuel shut-off switch probably?. next you need to take you battery out and have it load tested. Probably don't have enough amps to turn the starter motor providing you are setting in the seat, with the clutch pedal pushed all the way down with you foot, and the elect. PTO or manual engagement switch or lever is in the off position when trying to start it?.

If the battery Load tested good at your local auto parts store post back the results for problems elsewhere.

Have you tried it with the spark plugs removed? That engine requires valve adjustment periodically for the compression release feature to work. It is common for valves needing adjusted to cause the symptoms you describe but it could be other things.

I have the B&S Service Bulletin detailing how to adjust the valves IF you would like it. Address below, put in proper format and remind me, model number, what you want.

Walt Conner
wconner5 at frontier dot com

Almost hate to admit it, but after spending a little more time trying to track down the clicking sound when I turned on the key, I realized that it was the mower electric PTO engagement energizing. In other words, the engine had been shut down with the PTO switch in the on position, which locks out the starting circuit. Turned the switch off, problem solved.

Rollchard you would be susprised how many times that happens. At least you provided use feedback which IMO very important to others visiting this forum. We who respond are only guessing most of the time and hopefully or guesses leads to the fix of the problem. thanks for the feedback!