So my Z425 will only start by jumping the starter solenoid. After that, it runs great. If you try starting it with the key switch, it cranks the motor, but makes a weird "Brrrr" noise as its spinning and won't ever start the engine. Its sending 12 volts to the solenoid like it should when you turn the key to start position, so I'm assuming there is some sort of safety mechanism that's preventing it from starting but I'm not sure. Anyone have any ideas?