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

Rotor retention screw details

This rotor set screw is an engine replacement referenced as O.S. Engine OS22081811 and fits the model codes listed in the product title. It is used to retain the rotor assembly and prevent axial movement on compatible small-displacement RC engines.

Fit this part during routine maintenance or when repairing the crank and rotor assembly. Proper installation helps preserve rotor alignment and supports steady running behavior in engines that specify this screw.

Installation notes: confirm the OS22081811 part number against your engine manual or supplier listing before fitting, clean mating threads, and use a correctly sized driver to avoid rounding. Apply light, controlled torque; excessive force can damage the screw head or the mating threads. Check the seating during initial runs and retorque if required after break-in.

Role in upkeep: while not a tuning component, a securely mounted rotor reduces the risk of rotor shift under load, which can otherwise influence idle stability and throttle response.