YS F91AC Back Plate Screw YSF9153 Replacement Part (YS Engine)  [YSF9153]

F91AC rear cover screw overview

The YS Engine YSF9153 back plate screw is supplied as a hobby replacement for the YS F91AC engine rear cover. It is the fastening component that secures the back plate and adjoining parts, presented here strictly as an aftermarket spare.

Fit this screw when the original item is missing, damaged, or shows wear. Careful installation, proper seating and light torque work are important to avoid damage to the housing threads and mating surfaces.

During setup and tuning the screw helps retain correct back plate position so internal adjustments and port timing remain stable. Periodic inspection after running will confirm the fastener remains secure and thread engagement is satisfactory.