FZ91 Throttle Barrel Upgrade - YSF9355 by YS Engine  [YSF9355]

Throttle bore replacement for FZ91 carburetors

Supplied as YS Engine model YSF9355, this throttle barrel is an RC spare designed for the FZ91 carburetor family. The barrel creates the sliding bore for the carburetor slide; its surface condition plays a key role in throttle response, idle control, and mid-range running in glow-engine RC vehicles.

To install, remove the carb top and slide assembly, pull out the worn barrel, and press in the replacement, checking that O-rings and the bore align correctly. Confirm the slide travels freely and the barrel sits flush before final assembly.

When tuning or performing maintenance, look for bore scoring, check the mating face for flatness, and ensure the slide seal is intact to prevent unwanted air ingress. Cleaning and light lubrication of sliding surfaces will support repeatable throttle behavior when tuning and running.