My engine is an older vintage and has the metal grounding plate attached to a head bolt - that you can touch to the spark plug to kill the spark. Now that you confirmed what those wire will do - I might add a kill switch and remove the old spark plug grounding plate. On my year engine when the engine spins fast the governor arm gets pushed up which I think should close the butterfly/ reduce fuel to the engine. If the governor linkage directly (hard linkage) controls the butterfly on the carb., not sure what the throttle cable does or what is attached to the back of the throttle plate (via springs) that moves as a result of the throttle cable?