McGard 74039 Propeller Lock, 3/4-16 Thread - MerCruiser Alpha I/Bravo I, OMC Cobra, Mercury 70 HP+, Johnson/Evinrude 150 HP+ Outboards

The McGard 74039 propeller lock protects your outboard or sterndrive propeller against theft by replacing the standard prop nut with a locking nut secured by a unique key. The lock uses McGard's patented free-spinning collar design: if a thief attempts to remove it with pliers, a wrench, or any other gripping tool, the outer collar simply spins in place instead of turning the lock, so the propeller stays secured. The 74039 is built from naval brass and hardened stainless steel for corrosion resistance and long-term durability in a marine environment, and it is sized for a 3/4-16 thread.

This lock is designed for 3/4-16 thread propeller shafts on a range of sterndrive and outboard engines, including MerCruiser Alpha I and Bravo I (Stainless Steel, incl. X and XR), TRS, and Vazer sterndrives, OMC Cobra and King Cobra sterndrives, Mercury/Mariner 70 HP and larger outboards, Mercury Bigfoot 40 HP, 50 HP, and 60 HP (4 stroke) outboards, Optimax 75 HP and larger, Verado 135 HP and larger, and Johnson/Evinrude 150 HP and larger (2 stroke) outboards. Each lock comes with a plastic cap, the propeller lock itself, a matching key, and a washer, giving you everything needed to install it and secure your propeller right out of the box.

Specifications

• Brand: McGard
• Manufacturer Part Number: 74039
• Product Type: Propeller Lock
• Thread Size: 3/4-16
• Material: Naval brass and hardened stainless steel
• Color: Black
• Item Dimensions: 6.9 x 5.8 x 1.4 inches
• Weight: 0.7 pounds
• Included Components: 1 plastic cap, 1 propeller lock, 1 propeller lock key, 1 washer
• UPC: 083509740394

Fitment

• Sterndrive Engines: MerCruiser Alpha I, Bravo I Stainless Steel (incl. X and XR), TRS, Vazer
• OMC Cobra and King Cobra
• Mercury/Mariner 70 HP and larger (ex. 225 HP 4 stroke before 2005)
• Mercury Bigfoot 40 HP, 50 HP, 60 HP (4 stroke)
• Optimax 75 HP and larger
• Verado 135 HP and larger
• Johnson/Evinrude 150 HP and larger (2 stroke)

Frequently Asked Questions

What does the McGard 74039 propeller lock fit? The 74039 fits 3/4-16 thread propeller shafts on MerCruiser Alpha I and Bravo I (Stainless Steel, incl. X and XR), TRS, and Vazer sterndrives, OMC Cobra and King Cobra sterndrives, Mercury/Mariner 70 HP and larger outboards, Mercury Bigfoot 40 HP, 50 HP, and 60 HP (4 stroke) outboards, Optimax 75 HP and larger, Verado 135 HP and larger, and Johnson/Evinrude 150 HP and larger (2 stroke) outboards.

How does the McGard propeller lock prevent theft? It replaces the standard prop nut with a locking nut fitted with a free-spinning outer collar. If someone tries to remove it with pliers, a wrench, or any other gripping tool, the collar spins freely instead of turning the lock, so the 74039 stays secured to the shaft.

What is the thread size on the 74039 propeller lock? The McGard 74039 is sized for a 3/4-16 thread.

What material is the McGard 74039 made from? It is constructed of naval brass and hardened stainless steel, chosen for corrosion resistance and durability in a marine environment.

What comes in the box with the 74039 propeller lock? Each McGard 74039 package includes a plastic cap, the propeller lock, a matching propeller lock key, and a washer.

Does the 74039 fit MerCruiser Alpha One and Bravo One outdrives? Yes, the McGard 74039 is designed for MerCruiser Alpha I and Bravo I sterndrives, including the Stainless Steel, X, and XR versions, along with TRS and Vazer sterndrives.

What color is the McGard 74039 propeller lock? The 74039 is black.

How much does the McGard 74039 weigh? The 74039 propeller lock weighs 0.7 pounds.

Will the 74039 work on a Johnson or Evinrude outboard? It is designed for Johnson/Evinrude outboards of 150 HP and larger (2 stroke).

Is the 74039 the same lock used on McGard outboard motor and stern drive locks? The 74039 propeller lock uses the same patented free-spinning collar design as McGard's stern drive and outboard motor locks, applied specifically to securing the propeller.

What are the dimensions of the McGard 74039? The 74039 measures 6.9 x 5.8 x 1.4 inches.

Does the 74039 fit Mercury Optimax and Verado engines? Yes, it is designed for Mercury Optimax 75 HP and larger and Verado 135 HP and larger outboards.