Installing a pull starter, need some help on what to do (pics included)

[powerstroke]

You need to get yourself a butterfly rattle gun. This method allows you to undo things without having to stick objects between the chain and sprocket.

Ok. I will try bunnings tomorrow.

Also, what is the woodruff key?

 

[Fabian]

Also, what is the woodruff key?

Most of the time, the woodruff key will stick to the back face of the magnet when removing the magnet from the crankshaft.
To install the pull-start, you 'do not' need to remove the magnet, but you are well advised to make sure the air gap is correct when tightening up the nut; which will now hold the pawl disk to the magnet.