When you come off the seat, do you hear the PTO disengage and then the tractor shuts down- or does it seem to happen all at once? Maybe the seat switch is somewhat touchy or seat adjustment could be better. If your wife is lighter or shorter something to look at.

My wife is shorter and lighter and that was my first thought, but it also did it with me on level ground and I know I was in full contact unless the seat bottom is getting weaker. I hah thought of trying to fasten it in the down position to test it.

"My JD X500 dies while mowing. It restarts right away"

Dies while mowing with the PTO engaged, correct? It should not start without disengaging the PTO (pushing the PTO switch down). Do you have to push the PTO switch down to restart the X500?

The seat springs on the X500 can be moved to vary their effectiveness... have you tried to adjust them? It doesn't take much of lightening bun pressure on the seat to trigger the switch and stop the X500.

If you wife is shorter than you she might not be able to move the seat forward enough so she is positioned properly. My wife is short and can't get the seat forward enough to get the right position.

Justalurker, it restarts right away never had a problem with that. Yes we have to disengage the PTO. Never tried adjusting the seat springs. I did take the sensor out and put it back to make sure it was fully seated.
Thanks
Jerry