YS Engine YSS1027S Needle Valve Set for 50ST Series Replacement Needle for RC Model Engines  [YSS1027S]

YS Engine YSS1027S Needle Valve Overview

This needle valve set is a direct replacement part identified as YS Engine YSS1027S and made for the 50ST series glow engines. It replaces worn or damaged needle components and is intended for routine tuning and maintenance of remote-controlled model engines.

The function is simple and essential: needle valves regulate fuel flow to the carburettor, enabling fine adjustments to idle and mid-range mixture. When fitting this needle valve set, verify the YSS1027S part number against your engine service list and check nearby seals and seats for wear before completing installation.

Installation notes:

• Use a clean, debris-free workspace to avoid contaminating the fuel circuit.
• Remove the carburettor cap and carefully extract the old needle assembly, observing the orientation and any shims or springs.
• Fit the new needle set so it seats correctly and moves smoothly, then carry out a static fuel flow check before reinstalling the engine into the model.