4237 140 0601 STIHL Muffler – Genuine OEM Exhaust Part4237 140 0601 STIHL Muffler Genuine OEM Exhaust Part The STIHL Muffler (4237 140 0601) is a genuine OEM exhaust component designed to restore proper engine exhaust flow, noise reduction, and safe operation on select STIHL professional hedge trimmers. This muffler directs exhaust gases away from the engine while maintaining correct backpressure for optimal performance. Over time, mufflers can become clogged with carbon buildup, cracked from heat