Answering the need for secure propeller mounting, this guide highlights top boat propeller lock nut kits and related locking washers. These picks are best for saltwater durability, vibration resistance, and easy installation. Ideal buyers include casual weekend anglers, boat owners with frequent prop swaps, and sailors seeking reliable protection against propeller slippage.
| Product | Best For | Key Benefit |
|---|---|---|
| FASWORX MerCruiser Alpha Bravo Prop Propeller Nut Tab Locking Washer Kit | Alfa/Beta Mercury-Quipped Systems | Secures prop with tab washer to reduce vibration wear |
| doufuhua Marine Prop Nut and Lock Tab Washer Kit 18-3702 | Mercury/Mariner 30–60 HP | Complete kit with nut and two washers for easy replacement |
| HQPASFY Marine Propeller Lock Set | Mercury, MerCruiser, OMC with 3/4″-16 | Locking nut with free-spinning collar to deter unauthorized removal |
| IFERLA Outboard Prop Hub Nut Kit | Johnson/Evinrude/OMC 40–140 HP | All-in-one kit: nut, cotter pin, spacer for hassle-free install |
| MERCRURY OEM Propeller Nut & Tab Washer Kit 11-52707T | Mercury OEM applications | Official style kit designed for Mercury prop hubs |
MerCruiser Alpha Bravo Prop Propeller Nut Tab Locking Washer Kit Mercury Mariner
This kit includes a new propeller nut and locking washer designed for Alpha, pre-Alpha, Bravo 1, and Mercury-Mariner models with 75–125 HP. Best for boats that experience propeller loosening due to engine vibration. The locking tab washer helps extend propeller and shaft life by reducing movement under load. Caution: verify fitment with your model to ensure compatibility with your propeller hub design.
Marine Prop Nut and Lock Tab Washer Kit 18-3702
Includes a marine prop nut and two tab washers, compatible with Mercury/Mariner 30–60 HP engines. Best for standard outboard maintenance or replacement when upgrading older hardware. This kit fits Mercury 11-69578T1 and related models, offering a straightforward upgrade path. Limitation: ensure the kit’s part numbers align with your exact Mercury/Mariner model to avoid mismatches during installation.
Marine Propeller Lock Set Compatible with Mercury, MerCruiser, OMC
This lock set uses a brass and hardened stainless steel construction with a free-spinning collar in the locking nut. It prevents unauthorized removal and offers corrosion resistance in harsh marine environments. Best for boats using Mercury, MerCruiser, or OMC prop hubs that require a tamper-resistant lock. Limitation: brass components may require careful handling in very harsh saltwater conditions to minimize wear over time.
18-3702 Marine Prop Nut Kits for Mercury Prop Nut Kit 35-70 HP
HEBRAR’s 18-3702 kit fits Mercury 35–70 HP and similar models, including 11-69578A1, 11-69578T1, and 11-69578Q1. Best for Mercury-focused outboards and those upgrading to a complete nut and lock washer solution. This kit provides anti-rust properties and durable alloy steel construction. Caution: read part compatibility notes to ensure exact Mercury model alignment before purchasing.
IFERLA Outboard Prop Hub Nut Kit For Johnson/Evinrude
Designed to fit most Johnson/Evinrude/OMC motors from 40–140 HP, this kit includes a prop nut, cotter pin, and prop spacer. Best for installers who want an all-in-one replacement kit with compatibility across several legacy models. Benefit: the kit’s stainless steel components offer corrosion resistance. Caution: verify OEM part numbers before purchase to ensure exact fit.
MERCURY OEM Propeller Nut and Tab Washer Kit 11-52707T
Sold as an OEM Mercury prop nut and tab washer kit, this option is best for Mercury-centric maintenance where factory specifications are preferred. It helps maintain proper seating and secure latching against vibration. Caution: confirm exact Mercury model compatibility to avoid install issues with non-OEM hubs.
18-3716 Marine Prop Nut Kit for Johnson/Evinrude
Broad compatibility with Johnson/Evinrude motors and OMC, replacing GLM 22350, Evinrude/Johnson 175267, Mallory 9-73952, and OMC 175267. Best for boats needing a complete prop nut kit with spacer and cotter pin. Benefit: keeps the prop securely seated to prevent slippage. Caution: verify that this kit matches your OEM part numbers before purchasing.
Buying Guide
What should I look for in a boat propeller lock nut kit?
Key factors include compatibility with your engine’s make and HP range, the locking mechanism’s resistance to vibration, corrosion protection for saltwater use, and whether the kit includes all necessary components (nut, washers, cotter pin, spacer). A complete kit saves time and reduces the chance of missing parts during installation.
Locking mechanism vs. standard nuts
Locking tabs and free-spinning collars deter loosening from engine vibrations and unauthorized removal. If you operate in rough waters or salinity, choose brass or stainless-steel components with anti-corrosion coatings for longevity.
OEM vs aftermarket considerations
OEM kits ensure precise fit for Mercury or Mercury-compatible hubs, while aftermarket kits may offer broader compatibility. Always confirm the OEM part numbers and thread sizes (for example 3/4″-16) before purchase.
Installation notes
Ensure you align the nut and locking washer properly, secure with the appropriate cotter pin if included, and torque to the manufacturer’s general guidance. If you’re unsure about hub compatibility, consult your boat’s manual or the part number list on the kit.
Maintenance and replacement timing
Inspect the locking washer and nut during regular prop changes or maintenance. Replace if you notice lug wear, deformation, corrosion, or any looseness that could compromise propeller security.
Why choose a complete kit?
A complete kit reduces the risk of mismatched parts and simplifies maintenance. It provides a cohesive set of components designed to work together, improving reliability and speed of installation.
Quick FAQ
- What is a propeller lock nut? A nut designed with a locking mechanism (such as a tab washer or a free-spinning collar) to prevent propeller loosening due to vibration.
- Do I need a specific kit for my Mercury engine? If your engine uses Mercury hubs, OEM kits like the 11-52707T are a safe bet; otherwise, verify part numbers to choose a matching kit.
- Can I mix parts from different brands? It’s best to use a kit designed for your hub type to avoid fitment and corrosion issues.
- Is a locking washer necessary? Locking washers help prevent propeller loosening and extend propeller life in high-vibration environments.
- What should I replace during maintenance? Consider replacing the nut, lock washer, and cotter pin (if included) to ensure secure installation and optimal performance.
- How do I choose the right HP compatibility? Check your engine’s horsepower range and ensure the kit’s nut size and thread match your prop hub.