O.S. Engine OS21285220 Slide Valve Guide Screw for 10A and 10F Carburettors  [OS21285220]

Replacement procedure for 10A and 10F slides

This small guide screw is a direct replacement intended for the slide valve assemblies found in 10A and 10F carburettors on model glow engines. It sets the slide end stop and helps preserve consistent travel that affects idle behaviour and throttle feel.

Service steps are typical for carburettor work: remove the carburettor from the engine, dismantle the slide components to reach the guide screw, swap in the new screw, and reassemble while verifying smooth slide action. Check the slide face and ensure the screw runs true without forcing parts together; keep components organized to avoid losing small items.

From a tuning perspective, the guide screw contributes to slide alignment and movement repeatability. A properly installed guide screw makes throttle transitions more predictable and assists with reliable idle and high speed adjustments during routine tuning. This is an engine accessory intended solely for model use.