YS 91ST/91SR Carburettor Needle Seat Replacement - YSS9122 by YS Engine  [YSS9122]

Needle Seat Information

The YS Engine YSS9122 high speed needle seat is an RC replacement needle valve seat intended for use with YS 91ST and 91SR engine models. It acts as the contact surface that positions the high-speed needle and supports consistent fuel metering in glow-engine carburettors.

This item fits into the carburettor body at the needle valve location and should be inspected if needle play, fuel leakage, or unstable high-speed mixtures are observed. It is provided as a needle seat replacement for hobby RC engines rather than full-size applications.

For tuning, a properly seated needle seat ensures predictable needle closure and smoother top-end response, aiding more precise carburettor settings during break-in, scheduled maintenance, or track adjustments. Replace the seat when sealing fails or visible wear is evident.