I have a Yard-man MTD ride-on mower T604H that is now stuck in the starting position. Even if I turn the key to the off position, it is still cracking trying to start the mover. It killed my battery and unless I unplug the battery it will never shut off.
Can this be the ignition? I am about to order one but want to know if it could be something else.
If it is the ignition, how hard is that to install? Am I looking at removing half the engine?

Don't panic Hers a check list.

Common things causing this could be..

1.Faulty ignition switch or loose wire.

Check that all wires are properly connected to the switch. Ignition could be bad. Replace it.

2. The ground wire not connected to magneto. This is if someone maybe worked on the engine and removed the wire. Re-connect the black wire to its spade connector on the bottom side of the magneto.

3. Ground wire is broken, not properly installed or disconnected to stop switch. Make sure the wire is properly fitted in its connector on the control bracket (horizontal B&S, vertical and horizontal Tecumseh) or connected to the brake band, brake pad mechanism (vertical B&S, vertical Tecumseh

I would go with one. The switch is not a big deal except getting to it.