Throttle Lever Fixing Screw OS22781420 for O.S. Engine 2H, 3H, 20C, 20F, 40B, 40C, 60C Carburettors  [OS22781420]

Part description and fitment notes

The O.S. Engine OS22781420 throttle lever fixing screw is a small but crucial carburettor component designed to lock the throttle lever to the carburettor shaft on specified O.S. models. It is intended for model engine use where secure lever positioning matters for repeatable throttle action.

This fixing screw is compatible with carburettor codes 2H, 3H, 20C, 20F, 40B, 40C, and 60C. When fitted correctly it eliminates unwanted play at the throttle pivot and supports consistent throttle feel during tuning and operation.

Installation is simple: align the throttle lever with the shaft, insert the screw through the lever boss into the shaft thread and tighten carefully to avoid damaging threads. After fitting, confirm neutral and wide-open throttle positions before running the engine.

Functionally this is a service and maintenance part rather than a performance modification; keeping the fixing screw secure reduces linkage slop, aiding stable idle and predictable adjustments when setting needles or high-speed mixtures.