46" lawn tractor. I had to change the PTO belt. After I changed it, I realized I did not tighten one of the belt brackets to keep the belt in place. I stopped the tractor and fixed that. Now it won't start. When I turn the key, absolutely nothing happens.

I checked the battery, which is full. The interlocks seem to be working (that is, the seat interlock is working, and I hold the PTO handle all the way back when turning the key). I have a manual for the tractor, but it does not include any electrical diagrams at all.

Any ideas on what's wrong? Thanks!

"interlocks seem to be working " how can you tell that since the engine won't even turn over? You also have a clutch/brake safety switch as well as one for the blade. What happens sometimes is that something so simple is over looked that you keep missing it. Make sure the blade is disengaged and the clutch is fully deoressed. Your battery should read about 12.4 vdc with no load. If all switches are properly engaged and it still won't turn just come back and we can help you test the switches and solenoid. Chances are slim that these have failed while you tightened the belt guard.