O.S. Engine OS23818176 Universal Nipple No.9 for 20A, 20B, 20E, 20K, 21B carburettors  [OS23818176]

Universal Nipple No.9 for 20A/20B/20E/20K/21B

This universal nipple is an RC-scale carburettor replacement part intended to restore a secure fuel connection on the listed O.S. engine models. It serves as a direct service item for the fuel inlet or outlet interface where the original nipple is worn, damaged, or leaking.

Compatibility is limited to the models noted in the product title, so confirm the part visually against the carburettor before installation. The nipple is designed to fit the fuel seat or hose end used on those specific carburettors, providing a neat fuel path when seated correctly.

For installation, remove the old nipple, position the replacement so threads or seating align, and tighten progressively to achieve a firm, leak-free fit without over-torquing. After installation check for fuel tightness at idle and under typical running conditions before full operation.

In tuning and maintenance, this replacement plays a supporting role by ensuring the fuel delivery path remains sealed; keeping fuel connections serviceable helps maintain consistent engine response during setup and on-track adjustments.