O.S. Engine OS26711305 Needle Ratchet Spring No.4 - Carburettor Needle Spring  [OS26711305]

Needle Ratchet Spring No.4 for Carburettors

This is an RC-scale needle ratchet spring designed for use in O.S. Engine carburettor needle assemblies. It functions as the small return and detent spring in the needle valve ratchet, helping the needle hold position and provide predictable click increments for tuning.

In practical terms the spring supports consistent idle settings and smoother throttle transitions by maintaining reliable ratchet feel. Inspect the spring for deformation or loss of tension before reuse, and replace if the ratchet action feels sloppy or the needle does not index cleanly.

Installation notes: handle the spring with fine pliers, avoid bending the coil, and verify the needle moves freely through its seat after installation. Small adjustments and test runs on the bench or track will confirm correct seating without over-tightening the carburettor components.