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

Needle Valve Ratchet Spring No.4 Details

This ratchet spring fits into the needle assembly of O.S. Engine carburettors and supplies the detent force that keeps the needle in defined positions. Its role is to enable consistent, repeatable click steps for needle adjustment.

By preserving steady ratchet tension the spring contributes to consistent idle behaviour and predictable throttle changes. Inspect for coil deformation, diminished click feedback, or corrosion and replace when the ratchet no longer indexes reliably.

Handle the spring with care during installation, use fine pliers to avoid bending the coil, and ensure the needle travels freely after assembly. Confirm correct seating with short tests before returning the model to full service.