The nut that secures the flywheel (magneto rotor) to the end of the crankshaft of the STIHL 180 chainsaw. Its tightening determines whether the flywheel sits firmly.
Replace it if the thread is stripped, the flats are rounded off by the wrench, or the nut does not hold its torque. Before installing, check the key and the crankshaft thread: if the key is damaged, the ignition timing angle will shift.
Before buying, check your saw model: for Chinese saws and their analogues, parts of different generations may differ, so rely on the marking and comparison with the old part.
