Silencer Mounting Screw CSM4X17 O.S. Engine OS29025400 855 108FSR  [OS29025400]

RC silencer retention screw overview

The part code CSM4X17 and the identifiers 855 and 108FSR are listed in the original product naming. This screw is designed to attach a silencer to an RC engine exhaust assembly, keeping alignment stable under normal running vibration and while making tuning adjustments.

Use the screw as a direct replacement where your spare parts list specifies CSM4X17 or the matching numbers. Proper engagement of the thread and correct seating are key to preventing exhaust misalignment; inspect the thread condition before installing.

Being a small replacement fastener, it supports tuning and maintenance by reducing silencer movement that can upset exhaust sealing. It is not intended to alter engine performance directly but to preserve reliable exhaust fitment during setup.