Precision Carburettor Rotor OS40981200 by O.S. Engine  [OS40981200]

Precision rotor for carburettor assemblies

This rotor serves as a replacement rotating element for RC carburettor housings, restoring consistent throttle action and proper mechanical alignment inside the carburettor. When the rotor shows wear or damage it can introduce uneven throttle progression and cause idle instability. Replacing the rotor is a standard part service to recover predictable control.

Fitting the rotor is usually straightforward for an experienced hobbyist: detach the carburettor from the engine, record the rotor orientation and any thin shims or clips, clean the contact areas, and insert the new rotor with minimal axial play. Ensure the rotor rotates smoothly through its range without binding, then reassemble and check throttle return and idle behavior before operation.

For setup and tuning, an accurately seated rotor supports stable needle adjustments and smoother throttle transitions. Although not a tuning item by itself, replacing a worn rotor reduces uncertainty during mixture and idle calibration.