Sierra 18-3702

Secure your Mercury outboard propeller with confidence using this reliable propeller nut kit. Designed as a direct aftermarket replacement, it ensures your prop stays firmly in place during high-speed runs, rough waters, or everyday boating adventures. Crafted from high-quality stainless steel components, this kit resists corrosion and wear, extending the life of your propulsion system while maintaining peak performance.

Key Features That Stand Out

• Durable Construction: Marine-grade materials withstand saltwater exposure, freshwater splashes, and constant vibration without loosening or degrading.
• Complete Kit: Includes the prop nut, washer, and cotter pin for a hassle-free, all-in-one solution—no hunting for missing parts.
• Precision Fit: Engineered to OEM specifications, guaranteeing a snug, vibration-free installation on compatible Mercury models.
• Easy Maintenance: Simple design allows for quick inspections and replacements during routine propeller servicing.

Perfect Compatibility for Mercury Outboards

This kit fits a wide range of Mercury engines, making it a go-to choice for boaters with popular models from sportjets to offshore powerhouses. It's ideal for both recreational users and serious anglers who demand reliability on every outing. Always double-check your engine's specs for the best match, ensuring seamless integration without modifications.

Step-by-Step Installation Guide

Swapping out your prop nut is straightforward and doesn't require specialized tools. Here's how to do it right:

1. Power off and secure your boat on a stable trailer or lift.
2. Remove the old propeller by straightening and pulling the cotter pin, then loosening the nut counterclockwise.
3. Slide off the washer and propeller, inspecting the shaft for damage or debris.
4. Install the new washer first, followed by your propeller, then thread on the nut hand-tight.
5. Torque to manufacturer specs (typically 50-70 ft-lbs), insert the cotter pin, and trim excess.
6. Test run in calm water to verify smooth operation.

Pro tip: Apply a thin layer of marine grease to the shaft beforehand to prevent galling and ease future removals.

Why Boaters Trust This Kit for Long-Term Performance

Unlike generic hardware store parts that fail under marine stress, this kit delivers proven dependability. Boaters report fewer prop strikes and lost hardware, saving time and avoiding costly downtime. It's a smart upgrade for older engines prone to nut wear or anyone prioritizing safety on the water. Pair it with regular prop checks to catch issues early and keep your vessel running like new.

Essential Maintenance Tips

• Inspect the cotter pin after every 20 hours of use or post-beaching.
• Rinse with freshwater after saltwater trips to combat corrosion.
• Replace if you notice play, rust, or stripped threads—better safe than stranded.
• Combine with prop anode checks for full lower unit protection.