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

Overview of the throttle lever fixing screw

This O.S. Engine OS22781420 throttle lever fixing screw is an RC carburettor part made to hold the throttle lever securely on the listed O.S. carburettor models. It keeps the lever aligned with the carburettor shaft to preserve throttle geometry and repeatable control during running.

Compatibility includes the model codes 2H, 3H, 20C, 20F, 40B, 40C, and 60C. Proper installation prevents slack at the throttle arm pivot, helping deliver consistent throttle response and steadier tuning results.

To fit the screw, position the throttle lever on the shaft, push the fixing screw through the lever boss into the shaft thread, and tighten until firm without over-torquing to avoid stripped threads. After securing, verify both neutral and full-throttle positions before operating the engine.

As a maintenance item rather than a performance upgrade, this stainless steel retainer reduces play in the linkage and supports predictable needle and high-speed adjustments for more stable idle and throttle progression.