Carburettor Mixture Valve Assembly for O.S. Engine 61E-R & 91HZ-R OS29088300  [OS29088300]

Carburettor Mixture Control Overview

This mixture control valve assembly is a direct replacement component designed for use with O.S. Engine models 61E-R and 91HZ-R, specified for RC-scale model engine carburettors. It allows fine adjustment of the fuel/air mixture at idle and low throttle to help eliminate hunting and improve throttle progression.

Installed as an aftermarket replacement, the valve interfaces with the carburettor mounting and linkages typical of the listed O.S. models, so technicians can correct mixture issues without swapping the entire carburettor. Fitment is commonly done during scheduled maintenance or when previous needle settings no longer yield stable idle.

Tuning advice: proceed with small incremental changes and test in safe, controlled runs to assess idle and acceleration behaviour. Confirm that linkages move freely and that seals and threads are clean to reduce the risk of air ingress affecting mixture readings.

Match the OS29088300 part code to your engine before fitting, and perform initial checks on a bench or via short tethered operation to ensure the mixture behaves as expected under load.