Honda 8 hp question

[moosehunter]

I have a cement mixer with a 8 hp honda. It won't shut off. Coming out of the side of the block is a yellow wire I believe is a low oil shut off. ComIng from behind the flywheel cover is a black wire. Both wires go to a small unit mounted near the fuel tank then a wire goes to the on off switch. 
The switch will not shut off the engine. I unplugged both wires and grounded them , still keeps running. 
 My thought is that the black wire goes to the coil and should kill the motor if I ground it. 
 Anyone know for sure?

[sawguy21]

That is correct. The black wire is probably off the coil.