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

Carburettor Needle Ratchet Spring No.4 Overview

This small ratchet spring is designed for use inside O.S. Engine carburettor needle assemblies. It provides the detent tension for the needle ratchet so the needle holds indexed positions and produces predictable click increments during tuning.

Practically, the spring helps maintain steady idle settings and improves throttle response by keeping a consistent ratchet feel. Check the part for flattened coils or weakened tension before reinstalling; replace it if the ratchet action feels loose or the needle fails to index cleanly.

For installation, use fine pliers to position the spring without bending the coil, and ensure the needle moves freely through its seat after fitting. Perform careful bench tests and short runs to confirm correct seating before extended use.