JP, that same engine was used in the 3205 & 3208. I have a 3205 and my igniter box failed also. Mine would run but as it got warm it would fail to keep the engine running.
Prices are all over the place on that part too.
Cub Cadet is only asking $436 for the replacement part.
Here is a pretty good price on a replacement.
https://npwparts.com/products/kawasa...1v-fd620d-more
You need to make sure that you are getting power to the box before you replace it. You should be getting 12 volts to the orange/white wire going in to the box with the key on. Check to be sure you have a good ground on the black/white wire also. If you don't have both of those the box won't work.
Verify those readings and check back. I can email you a schematic if needed or Roland probably can too. Good luck.