O.S. Engine OS29008219 Woodruff Key for 61, 65, 70, 90, 91 Crankshafts  [OS29008219]

Precise Woodruff key for O.S. engines

This Woodruff key is an RC-scale crankshaft locating part intended for use with O.S. Engine models 61, 65, 70, 90 and 91. It seats in the crankshaft slot to lock a hub, gear, or prop driver in correct alignment, helping preserve timing and reduce axial play while the engine runs.

Compatibility is limited to the listed O.S. Engine model sizes 61, 65, 70, 90 and 91 as named. Before installation, confirm the key fits the crankshaft keyway without force; forcing a mismatched key can harm the shaft or the slot. This item is provided as an aftermarket RC accessory for engine maintenance and repair.

Installation guidance (general):

• Remove the driver or gear assembly from the crankshaft using your engine's standard disassembly procedure.
• Inspect the crankshaft keyway and mating component for burrs or debris and clean as needed.
• Position the Woodruff key so its curved face matches the shaft contour, then slide the driver or gear back onto the shaft ensuring a snug fit without excessive force.
• After reassembly, verify endplay and smooth rotation before operating the engine.

Tuning and service role: the Woodruff key is a small but critical element for timing consistency and mechanical repeatability. Inspect regularly for wear, deformation, or surface fatigue and replace if radial looseness, rounded edges, or movement of the mating part is observed.