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

Product outline and role

The O.S. Engine OS22781420 throttle lever fixing screw is a dedicated carburettor component used to clamp the throttle lever to the shaft on specific O.S. carburettor models, ensuring steady lever alignment for model engine operation.

Fitment covers the carburettor model codes 2H, 3H, 20C, 20F, 40B, 40C, and 60C. When installed correctly the screw removes undesired play at the throttle pivot and supports consistent throttle behaviour during setup and running.

To install: align the throttle lever onto the shaft, insert the fixing screw through the lever boss into the shaft thread and tighten to a firm but modest setting to avoid thread damage. Recheck neutral and full-throttle positions after tightening.

It is primarily a maintenance item rather than a tuning upgrade; securing the fixing screw maintains precise linkage geometry which aids stable idle and predictable needle adjustments.