O.S. Engine OS25081306 Rotor Set Screw - Compatible with 35R/C, 40SP, 40P, 50  [OS25081306]

Secure retention for O.S. rotors

This rotor set screw is a direct replacement part referenced by O.S. Engine OS25081306 and intended for use on the O.S. 35R/C, 40SP, 40P and 50 small model engines named above. It acts as the fastener that secures the rotor assembly to the crank or hub in compatible RC engines.

Intended purpose and role: the screw provides axial retention to preserve rotor timing and dynamic balance during operation. As a serviceable item it should be checked at every teardown for wear or damage.

Installation and service guidance: verify the model compatibility listed before installation, remove debris from mating surfaces, fit the screw so the rotor is held without axial play, and recheck condition on each rebuild. Replace the part if any thread damage or head distortion is evident to prevent loosening in use.