Sierra Drain Plug 18-2454, Replaces 3854539, for OMC Cobra SX Sterndrive

The Sierra Drain Plug 18-2454 is a replacement drain plug engineered for OMC Cobra SX sterndrives. It is used to seal the drain/fill point on the drive housing, sealing against water intrusion and oil or lubricant loss during operation and storage. The plug features a 3/8 inch - 16 thread and is designed to be used with a matching O-ring (Sierra 18-7145) to maintain a watertight seal at the drain port.

This part directly replaces OEM number 3854539, allowing owners of OMC Cobra SX drive systems to source a correct-fit plug without needing the original manufacturer part. Keeping the drain plug and its O-ring in good condition is important maintenance for any I/O sterndrive, since a worn thread or failed seal at this point can allow lubricant to leak out or water to enter the lower unit.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-2454
• Product Type: Drain Plug
• Thread Size: 3/8 inch - 16
• Mating O-Ring: Sierra 18-7145
• Weight: 0.02 pounds
• Product Dimensions: 0.39 x 0.39 x 0.39 inches
• UPC: 808282339784
• Category: Sterndrive Engine Parts

Fitment

• OMC Cobra SX sterndrives

Replaces (OEM)

• 3854539

Frequently Asked Questions

What does the Sierra 18-2454 drain plug fit? The Sierra 18-2454 is designed for OMC Cobra SX sterndrives, sealing the drive housing's drain and fill port.

Does 18-2454 replace an OEM part number? Yes, Sierra 18-2454 directly replaces OEM number 3854539 on OMC Cobra SX sterndrives.

What thread size is the 18-2454 drain plug? It uses a 3/8 inch - 16 thread.

Does the drain plug come with an O-ring? The plug itself is sold as 18-2454; it is designed to be used with a matching Sierra 18-7145 O-ring for a proper seal.

Is the O-ring included with part 18-2454? The dossier lists 18-2454 as the drain plug and 18-7145 as the O-ring used with it as a separate part number, so check whether both are included in your order.

How much does the Sierra 18-2454 drain plug weigh? The Sierra 18-2454 drain plug weighs 0.02 pounds.

What are the dimensions of this drain plug? The 18-2454 drain plug measures 0.39 x 0.39 x 0.39 inches.

What is part 18-2454 used for? It seals the drain point on an OMC Cobra SX sterndrive housing, preventing lubricant loss and water intrusion.

Is Sierra 18-2454 a genuine replacement or aftermarket equivalent? 18-2454 is a replacement part manufactured by Sierra that is a direct equivalent to OEM number 3854539.

Will 18-2454 fit other OMC sterndrive models besides the Cobra SX? The listed fitment for 18-2454 is OMC Cobra SX sterndrives; no other drive models are specified for this part.