I've got a Husqvarna YTH150 Yard Tractor with a problem.

It starts and runs just fine. While sitting on the seat (switch
engaged) I disengage the brake and the engine dies. It's definately an
electrical death (as opposed to friction.)

I have checked all wires and have tried a new relay. The brake switch
is working as the engine will not turn over with out the brake engaged.
The seat switch tests out with a multimeter (and I have jumped it as a
test.)

With the engine at idle and brake engaged, activating the PTO (to
engage blades) also kills the engine. This is interesting to me as I
was able to engage the blades once - now pulling the PTO kills the
engine.

I have looked for any obvious wiring issues and have found nothing.

As a background to this issue; I was mowing the lawn when the thing
just quit. I assumed I had run out of fuel - wrong. I was able to
start the engine (with blades off and brake on) but can do NOTHING with
this machine at this point.

Any help would be GREATLY appreciated!