I have an ex eleccy board 110 with H14 fitted - there's a cut off switch on the bonnet that only comes into play once the PTO is engaged (stops the drunken stoodents stalling my start to the day) -
I do know there's a switch, bit like a series handbrake type, that the PTO lever pushes against once engaged, this lights a warning light and very loud buzzer (now unplugged!), I presume it also does something to the fuel cut off circuit. I think I have a wiring diagram lying around somewhere, will try and dig it out.
N.