YS Engine YSS9122 High-Speed Needle Seat for YS 91ST/91SR  [YSS9122]

Needle Seat Details for YS 91ST/91SR

The YS Engine YSS9122 high speed needle seat is an RC-scale replacement needle valve seat intended for use with YS 91ST and 91SR engine types. It provides the wear surface that centres the high-speed needle and helps keep high-speed fuel metering consistent in glow-engine carburettors.

This part is installed into the carburettor body at the needle valve location and should be checked whenever needle slack, fuel dripping, or unstable high-speed mixtures are present. It is described as a replacement part for hobby RC engines.

For tuning, a correctly fitted needle seat aids predictable seating of the needle and smoother high-rpm throttle response, helping with precise carburettor adjustments during engine break-in, regular servicing, or track-side tuning. Replace the seat if it no longer seals or shows wear.