O.S. Engine OS25881210 Carburetor Rotor for 40L-R and 55HZ-R  [OS25881210]

Carburetor rotor for 40L-R / 55HZ-R

This replacement rotor is an RC-scale carburetor component intended for use with O.S. Engine carburettors labeled 40L-R and 55HZ-R. It serves the mechanical function inside the carburetor assembly, controlling throttle-related rotational movement as part of mixture and idle adjustment on small glow engines used in model aircraft, cars, or boats.

Fit and role: the rotor matches the 40L-R and 55HZ-R rotor seating profiles and acts as the rotating element that interfaces with the carburetor slide and linkage. It is a maintenance and service part for hobbyists who perform routine carburetor servicing or swap worn internal parts to restore consistent throttle response.

Installation notes: this item is supplied as the single rotor component, meant to be installed during carburetor disassembly and reassembly. Observe the carburetor manufacturer’s recommended order of parts, check alignment and free movement after assembly, and verify idle and mixture adjustments during bench testing before placing the model back into service.

Tuning and service guidance: the rotor itself does not change tuning settings, but replacing a worn rotor can eliminate binding or inconsistent throttle feel that affects mixture stability. After replacement, confirm smooth travel of the slide and recheck needle settings and linkage geometry as part of standard tuning checks.