Bad Boy wont start

[Ultimate1]

I have a 2008 ZT model I started it and drove it with no problem but when I engaged the blade it died. I replaced the battery but I still get nothing completely dead. Any ideas?

 

[bertsmobile1]

Usual suspect is the seat switch.
Mower thinks you are not in the seat so cuts out when the PTO is engaged.
Second option is the PTO switch itself but they are a lot more robust than the seat switch.
Then there is the wiring between the seazt switch, PTO switch & coil cut out.