O.S. Engine OS25081202 Airbleed Screw for 35RC 40SP 40P 50 engines  [OS25081202]

Airbleed screw for RC nitro engines

This airbleed screw is an RC-scale carburettor component designed to fit O.S. Engine models 35RC, 40SP, 40P, and 50. It provides a serviceable bleed point for low-speed mixture adjustment without altering the main needle assembly, allowing finer control of idle and initial throttle response during track or field tuning.

Compatibility is limited to the engine model codes listed above. The part is intended for use on nitro RC engines' carburettor airbleed ports and should be treated as a direct-replacement service part. Confirm fitment by matching the existing airbleed screw configuration on your carburettor before installation.

Installation is straightforward for experienced hobbyists. Remove the carburettor top or access cap as required, back out the old airbleed screw, and thread in the replacement until it seats. Make adjustments in small increments and test throttle and idle behavior between changes. The component’s tuning role is to fine-tune the air/fuel mixture at low throttle openings rather than to set full-throttle mixture.

Routine maintenance: inspect the screw and threads for deposits, ensure a secure fit, and replace if the seating surface or thread integrity is compromised. Store spare parts in a clean container to avoid contamination that could affect carburettor performance.