FZ High-Speed Needle Seat YSF1555 by YS Engine - Carburettor Part  [YSF1555]

Needle seat for high-rpm performance

The YS Engine YSF1555 FZ high-speed needle seat restores consistent top-end fuel metering in glow-engine carburettors. Its FZ profile determines how the high-speed needle seals at higher revolutions, helping maintain steady mixture control.

Fitting the seat is simple with basic hand tools: remove the carburettor bowl, withdraw the needle assembly, and install the replacement seat. Be careful to avoid cross-threading and prevent contamination; applying a small amount of lubricant to the needle can aid smooth operation.

While the seat is not a tuning part by itself, a correctly seated and clean needle seat is essential for repeatable needle settings and predictable throttle response. Check for debris regularly and confirm free needle movement after reassembly.