O.S. Engines

21XM Version II Air-Cooled Outboard Marine

Engineered to take down the competition!

Take down the competition with the 21XM Version II Outboard Marine engine from O.S.! It retains many of the features found on the successful 21XM, including the 20J carburetor and #8 glow plug. New additions include efficient air cooling, a larger muffler and more!

Displacement: 0.21 cu in. (3.5 cc) Output: 1.3 hp (25,000 rpm) RPM Range: 3,000-25,000 Weight: 24 oz (682 g) Bore: 0.654 in (16.6 mm) Stroke: 0.630 in (16 mm) Requirements: Glow fuel with 10-30% nitromethane content (use 20% for break-in), Glow plug igniter, Starting belt, Shore equipment
Please note: because of the competition nature of this engine, it is not covered by the O.S. 2-year limited warranty.

Also note: this engine starts and runs in a clockwise direction at the starter cone. Any attempt to start the engine in a counter-clockwise rotation may cause serious damage to the engine. Because of the clockwise rotation, the crankshaft features reverse threads.