O.S. Engine OS42525310 S-25 Silencer O-ring Replacement for RC Mufflers  [OS42525310]

S-25 Silencer O-ring Overview

This S-25 silencer gasket from O.S. Engine is supplied as a single replacement O-ring intended for mufflers and silencers that accept the S-25 profile. The part is listed alongside references F-6020 and FSa-155 and is designed to restore a tight exhaust joint on model engines, limiting blow-by at the silencer connection.

Fitting is simple: remove the silencer, clean the mating face of any burrs or carbon deposit, seat the O-ring into its groove, and reassemble while ensuring even compression. Take care not to twist the ring during installation and verify the joint at low idle to confirm there is no exhaust leakage.

When tuning, a correctly seated silencer gasket helps preserve consistent backpressure at the outlet, which can aid steady idle and smoother throttle response on glow engine models. Replace the O-ring whenever you notice hardening, cracking, or permanent deformation as part of routine service.