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McGard 74039 Propeller Lock 3/4-16 Thread for MerCruiser Alpha Bravo Outboards

Manufacturer

McGard

<h3>About McGard: Over 60 Years of Wheel Security Innovation</h3><p>Few brands can claim the kind of singular focus and proven track record that McGard brings to automotive security. Founded in 1964 in Orchard Park, New York, McGard grew out of L.D. McCauley, Inc., a precision machining company whose early work on government contracts for NASA and the military gave it a deep expertise in specialized alloy steels. When company founder Lewis D. McCauley designed and patented a security nut to prevent the theft of automobile rims and tires, a new industry was born — and McGard has been defining it ever since.</p><p>Today, <strong>McGard</strong> is recognized as the nation&apos;s leading manufacturer of mechanical anti-theft devices, supplying wheel locks and security fasteners to automotive OEMs, aftermarket customers, fleets, and marine operators across the globe. The company&apos;s manufacturing remains rooted in Orchard Park, operating from a modern 185,000-square-foot facility where every product is held to exacting internal quality standards.</p><h3>Why McGard Wheel Locks Stand Apart</h3><p>At the core of McGard&apos;s product lineup are its legendary <a href="/441-mcgard-wheel-lock-18100">wheel locks</a>. Unlike conventional lug nuts, each McGard wheel lock is a one-piece design that functions like a regular lug nut during everyday use but requires a unique, computer-generated key tool for installation and removal. McGard uses only restricted-chemistry steel manufactured specifically for its products, and every lock is through-hardened and tempered throughout its entire cross-section — not just surface-treated. This approach delivers a depth of hardness that resists even the most determined removal attempts. All McGard locks and lug nuts meet or exceed OEM proof load standards of 135,000 to 160,000 PSI, and the concentricity of the bearing surface is machined to a standard 30% more precise than OEM requirements.</p><p>That engineering excellence is why McGard has become an Original Equipment wheel lock supplier to more than 30 automobile brand names worldwide, including Ford, General Motors, Chrysler, Toyota, Honda, Nissan, and Subaru. Whether you&apos;re protecting a daily driver or a set of custom aftermarket wheels, McGard&apos;s <a href="/441-mcgard-wheel-lock-set-16214">wheel lock sets</a> offer a straightforward, highly effective security solution.</p><h3>Complete Wheel Hardware Solutions</h3><p>McGard&apos;s expertise extends well beyond individual locks. The brand&apos;s <a href="/441-mcgard-wheel-installation-kit-14954">wheel installation kits</a> provide everything needed to properly mount aftermarket wheels, typically bundling lug nuts, wheel locks, a key, and chrome valve stems into a single convenient package. It&apos;s the kind of thoughtful, all-in-one approach that reflects McGard&apos;s deep understanding of what installers and enthusiasts actually need.</p><p>Complementing the locking hardware is McGard&apos;s extensive range of <a href="/441-mcgard-wheel-lug-nut-7676">wheel lug nuts</a>. Available in a variety of seat styles, thread sizes, and finishes — including chrome-plated and spline-drive designs — McGard lug nuts are engineered to the same exacting standards as the company&apos;s locks. Every nut is precision-machined and designed to meet or exceed OEM specifications for torque performance and structural integrity.</p><h3>A Trusted Name Across Industries</h3><p>While automotive wheel security is McGard&apos;s best-known specialty, the brand also produces a complete line of marine security products — including stern drive locks, propeller locks, and outboard motor locks — as well as security fasteners for government, military, and infrastructure applications. This breadth of expertise speaks to a company that has spent decades solving real-world theft and tamper-resistance challenges across many demanding environments. For drivers, enthusiasts, and fleet managers who refuse to leave wheel and tire security to chance, McGard remains the definitive choice.</p>

Part Number

74039
06/01/2036 4:58 PM
Sale Price

$70.27

In Stock (10+)

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Usually delivered within 2 days

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Live-in-stock inventory

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Fitment guaranteed

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Product Details

The McGard 74039 Propeller Lock provides essential theft protection for your boat's propeller both in and out of the water. This marine-grade security lock is engineered specifically for stern drives and outboard motors, offering peace of mind at the dock or on the trailer.

Key Specifications:

  • Thread Size: 3/4 inch x 16
  • Overall Length: 1.025 inches
  • Hex Size: 1-1/16 inch
  • Construction: Naval brass and stainless steel for superior corrosion resistance
  • Includes one lock and one key

Compatible Applications:

  • MerCruiser Alpha I, Bravo I (including X and XR models), TRS, and Vazer stern drives
  • OMC Cobra and King Cobra stern drives
  • Mercury/Mariner 70 HP and larger (2-stroke) and 40 HP and larger (4-stroke) outboards
  • Mercury Optimax 75 HP and larger
  • Mercury Verado 135 HP and larger
  • Johnson/Evinrude 150 HP and larger (2-stroke) outboards

McGard's marine propeller locks are designed for durability in harsh saltwater and freshwater environments, using premium materials that resist corrosion and provide years of reliable security. The unique key pattern helps prevent unauthorized removal of your valuable propeller.

Products specifications

Propeller Lock Style

Outboard motor

Propeller Lock Thread Size

3/4 in. x 16

Quantity

Sold as a kit.

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