O.S. Engine OS25881700 carburettor retainer for 40L carburettors  [OS25881700]

Carburettor retainer overview

This O.S. Engine OS25881700 carburettor retainer is an RC-scale replacement part intended to secure 40L carburettors in nitro engine assemblies. It performs a simple but important mechanical role: keeping the carburettor indexed and stable against the engine housing so throttle linkage and needle adjustments remain consistent during use.

Installation is straightforward for hobby technicians familiar with engine installation. Fit the retainer to the engine flange using the original mounting points, verify the carburettor sits square in the intake, and check throttle arm alignment before final tightening. Use the same mounting screws and hand-tighten to a firm feel, then re-check after a short run to confirm there is no loosening.

In tuning work the retainer helps preserve throttle response and idle consistency by preventing minute shifts in carburettor position that can alter air and fuel mixture. When swapping carburettors or performing routine maintenance, the retainer aids repeatable reassembly so baseline settings remain useful between sessions.