40L-R / 55HZ-R Carburetor Rotor - OS25881210 by O.S. Engine  [OS25881210]

Replacement rotor engineered for 40L-R and 55HZ-R

This replacement rotor is a precision carburetor component made for O.S. Engine carburettors marked 40L-R and 55HZ-R. It supplies the rotating action within the carburetor assembly that governs throttle movement and contributes to mixture and idle control on small glow engines used in model aircraft, cars, or boats.

Fit and role: The rotor matches the seating profiles for 40L-R and 55HZ-R units and functions as the rotating element that interfaces with the carburetor slide and linkage. It is intended as a service part for hobbyists replacing worn internals to restore consistent throttle response.

Installation notes: Supplied as the single rotor component for installation during carburetor disassembly and reassembly. Follow the carburetor manufacturer’s recommended parts order, check alignment and free movement after assembly, and verify idle and mixture adjustments on the bench before returning the model to service.

Tuning and service guidance: The rotor itself does not alter tuning settings, but replacing a worn or damaged rotor can remove binding and improve mixture stability. After replacement confirm smooth slide travel and recheck needle settings and linkage geometry as part of routine tuning checks.