I have a John Deere Z225 mower that would turn over but not start. Power was not going to the carburetor solenoid so the gas was blocked. There was also no power going to the PTO switch or to the hour meter. After a lot of puzzling time tracing wires I realized the problem was in the fuse box. There were no blown fuses but there was a yellow wire connected to the back of an empty slot that had no 12v power. I jumped it to the red fused box next to it and everything worked fine. I learned that a fuse box doesn't just hold fuses. If any wires are connected to an empty shot then there is a built in wire that you can't see. I hope this post saves someone the anguish I went through. Start with the fuse box, not just the fuse.