O.S. Engine OS27902000 Crankshaft for 61SX-H and 61RX-H nitro RC engines  [OS27902000]

Crankshaft for 61SX-H / 61RX-H

This O.S. Engine crankshaft is an RC-scale replacement part intended for use in O.S. 61SX-H and 61RX-H nitro engines. It serves the core mechanical role of converting piston motion into rotational force and is offered as a direct swap where the original part has worn or failed.

Compatibility is limited to the listed model codes, so confirm your engine matches 61SX-H or 61RX-H before ordering. Installation requires basic engine disassembly and attention to bearing condition and crankpin fit; use the correct sized bearings and verify end-play and lateral runout during reassembly. If you rebuild the engine, inspect the connecting rod and crankcase mating surfaces for wear to ensure an even load distribution.

For tuning and setup, the crankshaft’s balance and runout affect vibration and peak performance in nitro RC engines. After installation, perform a static balance check and a low-speed break-in run while monitoring for unusual noise or oil leaks. Proper break-in and gasket sealing help maintain durability and predictable throttle response.

Use this crankshaft when replacing a worn or damaged unit in 61SX-H and 61RX-H nitro engines, and follow standard engine rebuild checks for bearings, runout, and sealing to restore reliable operation.