74039 Marine Propeller Lock Set For Mercury MerCruiser OMC 3/4"- 16 Thread Size

Marine Propeller Lock Set for Mercury, MerCruiser, and OMC

This marine propeller lock set is a security device that replaces threaded prop nut hardware with a locking system compatible with 3/4"-16 shafts, matching part number 74039.

Overview

The marine propeller lock set for Mercury, MerCruiser, and OMC secures your propeller against theft with a durable keyed lock. Designed for 3/4"-16 threaded stern drive and outboard shafts, this lock set replaces the standard prop nut and washer. It's an easy way for boat owners to add security to their investment without altering the propeller or shaft.

Built For Performance

• Machined from corrosion-resistant stainless steel and brass to withstand saltwater and freshwater exposure
• Features a recessed lock face that is difficult to grip with removal tools
• Includes a matched key set for simple installation and removal by the owner
• Maintains proper clamping force to keep the propeller hub seated correctly
• Universal 3/4"-16 thread fits a wide range of outboard and sterndrive applications

Fits These Machines

• for Mercury outboard engines with 3/4"-16 propeller shaft
• for MerCruiser Alpha One and Bravo One sterndrives
• for OMC Cobra sterndrives with 3/4"-16 thread
• for OMC Stringer series drives

On-The-Job Use

• Securing a stainless steel propeller while the boat is on a trailer or moored overnight
• Preventing theft at a busy public boat ramp after a day of fishing
• Adding an extra layer of security on a wakeboard or ski boat during a weekend on the lake
• Protecting a high-lift propeller on a commercial water taxi or work skiff

Specs At A Glance

Good To Know

Q: How do I check if my propeller shaft has 3/4"-16 thread? A: Measure the shaft diameter with a caliper and count 16 threads per inch using a thread gauge; most mid-range Mercury and MerCruiser drives use this standard.

Q: Will this lock set work with a stainless steel or aluminum propeller? A: Yes, the lock set functions with any propeller that uses a standard 3/4"-16 shaft thread and a hub kit that accommodates the lock's depth.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.