Mixture Control Valve for O.S. Engine 61E-R and 91HZ-R - OS29088300  [OS29088300]

Replacement Mixture Valve 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 helps you adjust the fuel/air ratio at idle and low throttle to improve throttle roll-on and idle steadiness.

As an accessory for the identified O.S. models, the valve installs into the carburettor mounting and links already present on those engines, allowing targeted mixture correction without changing the whole carburettor. It is commonly fitted during servicing or when needle changes have not restored consistent idle.

Tuning practice: make slight adjustments and evaluate engine behaviour under controlled conditions, concentrating on idle stability and response to throttle input. Check that linkages are free and mating surfaces are clean to prevent air leaks that can obscure mixture settings.

Confirm the OS29088300 part number matches your engine before fitting. Perform initial tests on a stand or via short tethered runs to validate mixture adjustments safely.