Sierra Prop Nut 18-3785 for Mercruiser Prop Hardware

The Sierra Prop Nut 18-3785 is a replacement propeller nut engineered for Mercruiser prop hardware applications. It secures the propeller onto the propeller shaft, keeping the prop properly seated and preventing it from working loose under the vibration and load of normal running conditions. As a dedicated hardware component, it is a simple, purpose-built part meant to restore the original clamping function at the shaft when an old nut is worn, corroded, or lost during a prop change.

This prop nut is sold as a standalone hardware item, making it a straightforward, low-cost way to complete a propeller installation or keep a spare on hand for routine prop swaps and maintenance. Because it is categorized specifically under Mercruiser prop hardware, it is intended for use with compatible Mercruiser propeller shaft setups.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3785
• Product Name: Prop Nut
• Category: Mercruiser Prop Hardware
• Weight: 0.31 pounds

Fitment

Designed for Mercruiser prop hardware applications.

Replaces (OEM)

No OEM cross-reference numbers are listed for this part.

Frequently Asked Questions

What is the Sierra Prop Nut 18-3785 used for? It secures a propeller onto the propeller shaft on compatible Mercruiser prop hardware setups, holding the prop firmly in place during operation.

Is the 18-3785 prop nut sold individually? Yes, Sierra part number 18-3785 is sold as a single Prop Nut, not as part of a kit.

How much does the Sierra 18-3785 prop nut weigh? It weighs 0.31 pounds.

What category of hardware does part 18-3785 belong to? The Sierra 18-3785 is listed under Mercruiser Prop Hardware.

Does the 18-3785 prop nut fit all Mercruiser drives? Specific engine, drive, or year fitment is not specified for the 18-3785; confirm compatibility with your particular Mercruiser prop hardware setup before ordering.

Is this a genuine Sierra part or an aftermarket copy? Part number 18-3785 is a genuine Sierra part, sold under the Sierra brand.

When should I replace my propeller nut? A prop nut like the Sierra 18-3785 should be replaced if it is worn, corroded, or removed and damaged during a propeller change, since a compromised nut cannot reliably retain the prop on the shaft.

What else do I need besides the 18-3785 prop nut to install a propeller? The 18-3785 Prop Nut is the retaining nut only; other hardware such as washers, tab washers, or cotter pins used in your specific prop assembly are separate components not included with this part.

What material is the Sierra 18-3785 prop nut made of? Material composition is not specified for the Sierra 18-3785 Prop Nut.

What is the UPC for the Sierra 18-3785 prop nut? The Sierra Prop Nut 18-3785 is identified by UPC 808282185510.