O.S. Engine OS22081811 Rotor Retaining Screw for 10FSR / 10/15/25FP / FS20 / FS40 / 21 / 31 / RE  [OS22081811]

Set screw function and fit

Referenced as O.S. Engine OS22081811, this rotor retaining screw is a replacement component for the model numbers listed in the product name. Its main function is to hold the rotor in place and prevent axial movement on small RC engines.

Use this part when rebuilding the crankcase or performing routine engine maintenance. Correct installation ensures the rotor stays aligned and supports repeatable engine response.

Installation notes: first confirm the OS22081811 part number with your engine manual or supplier listing, clean mating threads, and install with an appropriate driver to prevent rounding. Tighten with measured torque; too much force can damage the screw or mating threads. Check seating after break-in runs and retorque if required.

Tuning impact: though not a tuning upgrade, a secure rotor helps avoid shift-related inconsistencies that can affect idle and throttle feel during tuning sessions.