I have a Simplicity "Regent" Hydrostatic mower with a 14 HP (B&S). 1. What would cause the engine to cut off when I try to disengage the brake/clutch or engage the PTO? 2. The starter has a box mounted to it. I think it is a solid state ignition upgrade but I am not sure. It has a red (12 Volt)power and a black (Ground?) wire. The black wire is not attached anywhere. Can I ground it to the engine?