YS Engine YSF9153 Back Plate Screw F91AC replacement part  [YSF9153]

Back plate screw for F91AC

This YS Engine YSF9153 back plate screw is an RC-scale replacement part intended for the F91AC engine back plate. It serves as a direct fastener to secure the engine rear cover and associated components, and is described here strictly as a hobby-grade spare.

Use this screw where the original back plate fastener is worn, lost, or damaged. Installation focuses on correct seating and cautious tightening to preserve threads and the mating surfaces of the engine housing. The part is intended to restore mechanical integrity of the back plate assembly without altering engine performance or tuning characteristics.

For tuning and maintenance, the back plate screw plays a supporting role: it holds the back plate in the correct position so that internal adjustments and port timing remain consistent. Regular inspection after run sessions is recommended to confirm the screw remains secure and the thread engagement is intact.