FSa-72 Engine Crankcase OS44301000 Compatible Replacement by O.S. Engine  [OS44301000]

Overview of the FSa-72 crankcase

This crankcase is an RC-scale replacement part produced by O.S. Engine for the FSa-72 family of model engines. It functions as the main shell for the crank and bearing assemblies and is intended for rebuilds, repairs, or stocking as a spare for workshop use.

Compatibility is limited to the FSa-72 designation shown in the product name, so confirm the engine model before ordering. The crankcase aligns bearings and the crankshaft while providing mounting interfaces for the cylinder and gearbox; careful alignment during assembly preserves bearing life and smooth running.

Installation notes: remove the engine from the model and strip components following the original sequence, transfer bearings and internals where applicable, and reassemble checking end-play and concentricity. Keep the work area clean to avoid contaminants entering the crankcase and inspect threaded holes and mating faces for damage.

Tuning and service role: although the crankcase does not directly tune engine output, a correctly assembled and intact crankcase supports consistent crankshaft behavior and sealing, aiding stable tuning from carburetor and exhaust adjustments.

Keep this OS44301000 crankcase as a direct spare for FSa-72 engine servicing and follow established rebuild procedures to maintain reliability.