O.S. Engine OS27902000 Crankshaft for 61SX-H and 61RX-H Engines  [OS27902000]

Replacement Crankshaft for 61SX-H and 61RX-H

This O.S. Engine OS27902000 crankshaft is a direct replacement intended for O.S. 61SX-H and 61RX-H nitro engines. It converts piston motion into rotational drive and is supplied as a swap-in option when the original unit is worn or damaged.

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

For tuning and setup, crankshaft 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 while monitoring for unusual noise or oil leaks. Proper break-in and careful gasket sealing help maintain durability and consistent throttle response.

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