O.S. Engine OS29008219 Crankshaft Woodruff Key Compatible with 61, 65, 70, 90, 91  [OS29008219]

Woodruff key: crankshaft locating piece

This Woodruff key serves as a locating component for RC crankshafts, specified for O.S. Engine model sizes 61, 65, 70, 90 and 91. It engages the crankshaft slot to hold a hub, gear, or prop driver in fixed rotational position, helping maintain accurate timing and minimising axial play.

Compatibility is confined to the stated O.S. Engine sizes 61, 65, 70, 90 and 91. Always check that the key seats cleanly into the crankshaft keyway before forcing parts together; a mismatched key can damage the shaft or the slot. This is an aftermarket replacement part intended for engine upkeep and repair.

Installation guidance (general):

• Remove the prop driver or gear from the crankshaft following your engine's disassembly steps.
• Examine and clean the crankshaft keyway and mating surface from burrs, corrosion or debris.
• Align the Woodruff key so the curved side conforms to the shaft radius, then slide the driver or gear back onto the shaft making sure it seats without undue force.
• Recheck endplay and rotation smoothness before running the engine.

Tuning and service role: the Woodruff key is small but vital for repeatable timing and mechanical stability. Include it in routine inspections and replace if you see wear, distortion, or if the mating component shifts during operation.