Check the wires on the solenoid
Their should be 2 wires at the base
The orange wire should go from 0 to 12 V when the key is turned to start
The green should go from open circuit to ground when the key is turned to start
If the orange wire does not show 12 V ( or battery voltage ) then the key switch is faulty or the fuse is blown
If the green wire does not show ground then you have a problem with the PTO switch, neutral switch , or kill relay