F91AC Rear Engine Back Plate - YSF9147 by YS Engine  [YSF9147]

F91AC back plate overview

This YS Engine back plate YSF9147 is an RC-scale replacement component labelled for the F91AC family and serves as the engine's rear housing plate. It functions as the mounting surface for seals and internal components that align the crankcase rear section, and is intended for model engine repair and routine servicing rather than performance modification.

For installation, confirm the part number on the package before disassembly, clean mating surfaces, and reuse or replace the gasket or sealing material as required by your engine's service practice. Tighten fasteners evenly in a crisscross pattern to avoid distortion, and inspect the seal line after the initial run for any signs of leakage or misalignment.

Tuning and service role: this back plate maintains rear-end alignment for moving parts and helps preserve internal sealing that affects idle stability and compression. When replacing the plate, verify clearances and bearing seating during reassembly to keep the engine operating as intended.