GT55 Engine Parallel Key OS29708200 by O.S. Engine  [OS29708200]

Shaft key for GT55 tuning setups

This O.S. Engine parallel key fits GT55 RC engines to lock hubs and flywheels to the crankshaft, transmitting torque while preserving component alignment. Its precision finish helps avoid slipping during aggressive tuning or high-RPM testing.

To install, align keyway and hub slot, slide the key into place so it seats correctly for the hub design, then assemble the flywheel and check for true rotation. Inspect the part after intense runs and swap it out at the first sign of deformation.

Use the key as a reference point for repeatable timing when adjusting ignition or carburetion settings. Avoid forcing the key into tight slots; a light press or tap is sufficient for most assemblies. This part is supplied as a serviceable spare for routine engine setup work.