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

Metering needle for 21M/21XM

This O.S. Engine metering needle is a replacement carburettor part intended for use with 21M and 21XM series RC engine carburettors. It serves the core function of controlling fuel flow through the carburettor needle valve, allowing finer adjustment of mixture for different engine conditions on nitro-powered RC models.

The needle features a stainless steel tip for wear resistance where the needle seats, while the shaft and taper are produced to match factory fit dimensions for the specified carburettor types. Installation requires removing the carburettor top and replacing the existing needle; final tuning should be done track-side with incremental adjustments to idle and main mixture settings to establish the desired response.

Use this part when you need a direct swap or when tuning calls for a replacement needle to restore consistent mixture control. This article describes the RC-scale application only and does not apply to full-size engines.