Walker won't start
I have had this similar problem before, It is usually a relay or safety switch, but here is what I do first to get by until it is fixed. I ran a wire from the battery to the 12V terminal (spade plug) on the starter. I put a push button in the line, so I can start it that way. If it turns over using this method then you have a relay or safety switch problem. I had so much trouble with one mower that I put a toggle switch in the instrument panel and ran a wire from it to the starter. To start click the key then hold the toggle switch until it starts.
The last time I had the problem it was on an MT model and the relay near the blower went bad. The is an easy fix. I would try that first. Look in the back of the illustrated parts book to see the electrical diagram to trace wiring
2-Walker 20 HP GHS, 1-Walker 26 hp GHS, 1-Walker 23 hp GHS, 42 and 48 GHS decks, 42 mulch deck, 42 discharge deck, 3-Honda WB, 3 Shind Trimmers, Stihl BR600 blower, Shind 260 edger, Two Shind Multi-tool with artic. clippers and chainsaw, Redmax 8000 blower, Redmax 7001 blower, Shind 803 Blower, Spyker walk spreader, sprayer for Walker mower, 3-Stihl chainsaws.