The clack you're experiencing is most likely from your engine kicking back against the sprag. This I would hazard a guess may create undo stress to the sprag retaining spring.
Check your plugs, wires, coils for issues.
When failing, the sprag will make that exact some sound when you are pushing the ignition button. Maybe once, then death, or occasionally at first slowly increasing frequency as the sprag spring loosens, then death. Then, if/when the retaining spring breaks, the starter will spin without properly engaging the sprag clutch.
Check your plugs, wires, coils for issues.
When failing, the sprag will make that exact some sound when you are pushing the ignition button. Maybe once, then death, or occasionally at first slowly increasing frequency as the sprag spring loosens, then death. Then, if/when the retaining spring breaks, the starter will spin without properly engaging the sprag clutch.
