Small Engines (Lawn Mowers, etc.): la110 john deere

Question
start mower leave off break then shuts off.
also start mower leave break on ,engage pto and shuts off
if safety where are they located

Answer
I would start by checking for wires around the clutch/brake pedal.

Wiring harness diagram:

http://www.circletractor.com/OemParts?_BREAKDISK=_4.9MM_WITH_HEAVY_DUTY_FINAL_DR

There are service manuals on the net but they can be pretty pricey, several hundred dollars.  Most of the electrical problems can be troubleshot with a simple 12v DC light or basic multimeter.

Did you follow the wiring to each safety switch indicated on the wiring harness diagram to make sure they are all connected?
Do you have a basic multimeter?

Eric