O.S. Engine OS21781970 10LA & 15LA Carburettor Needles Replacement  [OS21781970]

Precision 10LA and 15LA carburettor needles

This O.S. Engine OS21781970 twin needle set covers the 10LA and 15LA needle types used in small glow-model carburettors and is supplied as RC replacement parts for routine engine upkeep. The needles restore the factory adjustment interface and provide repeatable seating for consistent tuning work.

In operation the needle controls fuel flow at the carburettor needle valve, directly affecting mixture and idle behavior. Replacing a worn or damaged needle can resolve erratic idle, uneven throttle response, and the need for excessive mixture compensation during setup. The part is supplied as the direct replacement needle component rather than a multi-piece assembly.

Fitment and tuning advice: install this needle only in carburettors specified for 10LA or 15LA types, ensure correct seating and smooth travel, then adjust mixture and idle following your engine's normal procedure. Make small increments when tuning, observe engine reactions, and re-check needle seating after initial runs to confirm stable performance.