O.S. Engine OS47161100 Rocker Arm FSa-81 — Replacement rocker arm for FS-series RC engines  [OS47161100]

Rocker Arm for FS Engines

This rocker arm is a direct replacement component supplied under the O.S. Engine OS47161100 designation for FSa-81 style parts. Designed for RC-scale FS series engines, it serves the mechanical role of transferring cam motion to the valve train and is intended for routine maintenance, repair, or tuning of nitro-powered RC engines.

The text focuses on fit and function rather than specific measurements. Compatibility should be confirmed against the engine part code before installation, and replacement is typically performed during routine engine servicing or when valve movement shows wear. The part is presented as an OEM-fit option that restores correct valve actuation characteristics on FS-series engine assemblies.

Installation notes: remove rocker cover and inspect rocker geometry and valve clearance before fitting the new arm, verify free movement after assembly, and re-check engine timing and idle behavior on the model before full operation. Treat this strictly as an RC-scale engine part and do not use it outside model applications.