My Briggs 8B let's out a distinct clink or clank or ping or pang or spank now and then. It happens when I'm laying into the throttle from a low speed and comes right about the time I am about to ease off on the throttle. This part seems important because it seems to be around the height of torquing. One loud "sprack" and that's all, until the next time it happens. Sounds like metal on metal.