The Mercury Propeller Tab Washer, commonly identified by part numbers 14-816629K, 14-816629Q, 14-816629, and 816629, is a critical piece of propeller-retention hardware used on a wide range of Mercury Marine, Mercury Racing, Mariner, and MerCruiser applications.
Although small and inexpensive, this locking washer performs an important safety function by helping secure the propeller nut to the propshaft. Once the propeller nut is properly torqued, one of the washer tabs is bent against a flat on the nut, creating a positive mechanical lock that helps prevent loosening from vibration, shifting loads, acceleration, deceleration, and propeller thrust forces.
Why the Tab Washer Matters
The propeller assembly is subjected to constant load changes while the boat is operating. Even when a propeller nut is tightened to specification, Mercury designed the tab washer as an additional mechanical safeguard to help maintain proper retention of the propeller hardware.
A damaged, fatigued, or previously bent washer may not provide the same locking capability as a new part. For this reason, many technicians and performance boaters routinely replace the tab washer whenever the propeller is removed for inspection, service, or replacement.
Considering the cost of a propshaft repair, damaged lower unit, or lost propeller, replacing the tab washer is inexpensive insurance.
Broad Mercury & MerCruiser Fitment
The Mercury 14-816629K tab washer is used throughout a wide range of Mercury Marine, Mercury Racing, Mariner, and MerCruiser products. It is commonly found on Mercury outboards from approximately 75 HP through 300 HP, including numerous EFI, DFI, Optimax, Pro XS, FourStroke, Verado, Sportmaster, TorqueMaster, and Mercury Racing gearcase applications.
The same locking washer is also used on many MerCruiser Alpha One, Alpha One Gen II, and various Bravo drive systems utilizing traditional propeller nut locking hardware. Its widespread use across both outboard and sterndrive platforms has made it one of Mercury's most commonly used propeller hardware service components.
Six-Tab Locking Design
The washer features a multi-tab locking design that allows the installer to select the tab that best aligns with the propeller nut after final torque has been achieved. Once bent into position, the tab creates a positive lock between the washer and nut, helping prevent unwanted movement during operation.
This simple but effective design has been used successfully throughout Mercury's product line for decades and remains one of the most reliable methods of securing marine propeller hardware.
Cross Reference Information
The Mercury propeller tab washer is commonly referenced under several Mercury and aftermarket part numbers depending on production year, packaging, and supplier.
Current Mercury replacements include 14-816629K and 14-816629Q, while earlier versions may be identified as 14-816629 or simply 816629. Additional aftermarket references include 14-31210, 18-3200, and GLM 21200. These part numbers are frequently used interchangeably when sourcing replacement propeller locking hardware for Mercury outboards and MerCruiser sterndrives.
Recommended During Propeller Service
Whenever a propeller is removed for hub replacement, propshaft inspection, seal replacement, lower-unit service, or propeller changes, the locking hardware should be inspected. Installing a fresh tab washer helps ensure proper propeller retention and eliminates concerns about fatigue from previous installations.
For high-performance bass boats, offshore boats, fishing boats, recreational runabouts, and Mercury Racing applications, replacing the tab washer during routine service is considered a best practice.
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The Mercury 14-816629K, 14-816629Q, 14-816629, and 816629 Propeller Tab Washer is a small but essential component that plays an important role in propeller retention and drivetrain reliability. By providing a positive mechanical lock between the propeller nut and propshaft assembly, it helps protect valuable lower-unit components while supporting safe operation on the water.
Whether you're maintaining a Mercury Racing Sportmaster, Pro XS, Optimax, Verado, Alpha One, Bravo drive, or a recreational outboard, replacing the tab washer during propeller service is a simple step that helps ensure long-term reliability.