YS Engine YSF9151 Disc Valve Pin E-Ring F91AC  [YSF9151]

This small replacement part serves as the retention ring for the disc valve pin on YS F91AC series glow engines, provided here as an RC-scale accessory for routine maintenance and repair. It is intended to hold the disc valve pin in its groove and prevent axial movement that can affect valve operation.

Use this e-ring when replacing a worn or damaged disc valve pin retention component. During inspection, confirm the e-ring seats fully in the pin groove and that the pin turns freely without binding. If the ring shows deformation or loss of spring tension, replace it to restore secure retention of the disc valve assembly.

Notes on function and tuning: the e-ring itself does not alter engine timing but is a basic service item that helps maintain consistent valve movement; keeping the retention hardware in good condition supports predictable throttle response in RC glow engines.