O.S. Engine OS-13941 21XM Version II Precision Racing Engine  [OS-13941]

O.S. Engine #13941 - 21XM Ver.II
Price:
£379.35
Brand:
O.S. Engine
Model:
OS-13941
Condition:
Brand New
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O.S. Engine OS-13941 Performance Overview

The O.S. Engine OS-13941 provides a compact and focused performance profile for RC car and buggy use. It combines a high-rev capability with consistent behaviour for competitive running.

Engine Specs That Support Accurate Throttle Control

The OS-13941 has a 3.46cc displacement and is rated at 1.3ps at 25,000 RPM. Its 16.6mm bore and 16.0mm stroke produce efficient combustion and a controllable powerband.

Adaptable RPM Range for Multiple Track Types

With a practical RPM spread of 3,000 to 25,000, this engine suits both technical circuits and faster layouts, enabling drivers to dial in power for different conditions.

Featherweight Construction for Better Cornering

Weighing 670g, the OS-13941 reduces overall vehicle mass to help with corner entry and quick directional changes while maintaining structural resilience.

Specifications

  • Displacement: 3.46cc (0.211 cu.in)
  • Output: 1.3ps at 25,000 RPM
  • Bore: 16.6mm (0.654in.)
  • Stroke: 16.0mm (0.630in.)
  • Weight: 670g (23.6oz.)
  • Practical RPM Range: 3,000 - 25,000 RPM

The O.S. Engine OS-13941 is a capable choice for drivers after a compact, high-revving engine that balances performance with manageable handling traits.

What maintenance should I perform after each run session?

After each session, clean external grime, check for fuel leaks, inspect the glow plug, and ensure the head screws and mounting bolts remain tight.

Which carburettor settings suit different track conditions?

Use a slightly richer high-speed setting for dusty or loose surfaces and a leaner tune on clean, high-traction circuits to sharpen throttle response.

Can I upgrade internals for more top-end?

Minor upgrades like a matched tuned pipe and optimised carb tuning yield gains; major internal modifications are uncommon and should be done with caution to preserve reliability.

How do I check the engine is running at the correct mixture?

Examine glow plug colour after a run and monitor plug condition and exhaust soot; adjust needles incrementally until the plug shows a light tan for correct mixture.

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