Opps.!!

The retaing bolt is usually relitively easy to remove . the wire is held in by a #2 phillips head and then the neutral switch is then allows itself to be removed with a pair of long nose pointy pliers .
Just poke the two ends of the snipe nose pliers into the opposite holes in the switch itself and tighten the grip and pull. It should pop out. Make sure that there is a Oil catcher around even if you have already drained the oil. Could be a battle field dressing required.
Wash the switch out in white spirit and test the circut.
It's almost bullet proof.
Clean the orifice & replace the O ring on the switch if it hard or leaking put some good grease on the O ring and then push the switch back in and replace the screw and then the locking plate and retaining bolt.
Should work .
Yehaa .
I had the same problem.
Once you have over come the fear of failure its easy.
Ask Me.
Dave
Australia.