O.S. Engine OS22082350 Metering Needle for 21M & 21XM Carburettors  [OS22082350]

Metering needle suited to 21M/21XM carburettors

This metering needle from O.S. Engine is intended as a replacement for 21M and 21XM series carburettors and performs the function of regulating fuel flow at the needle valve, enabling finer mixture tuning for nitro RC model engines.

The component incorporates a stainless steel tip to reduce wear where the needle seats, and the shaft and taper are produced to align with factory fitments for the specified carburettor models. Installation is straightforward: remove the carburettor top and replace the existing needle, then perform careful on-track tuning with incremental idle and main adjustments to achieve the required performance.

Use this part for a direct swap or when tuning indicates the original needle is failing to maintain consistent mixture control. This note refers only to RC-scale engine use and not to full-size engines.