I am new to the mud motor world just bought a 23 horse gd lt. I am in the process of rebuilding the motor and was wondering how the timing advance keys worked. thanks for the help.

Its a notched flywheel key. Offsets the flywheel how ever many degrees the key is. Reason being the magnets in the flywheel that pass along the coils will pass 3 to 6 degrees early along coils making ignition from the spark plug just a lil bit sooner than normal.

out come,

Engine motor go fast, fast,

Hope this helped.

but if the key is notched how does it stay tight in the key way.

so it installs just like the stock one and were could i buy a new key

thanks for the help

Here is a good read for those wanting to know about advanced timing keys.
http://www.foxvalleykart.com/timing2.html