Mercury V6 Powerhead Stud Washer and Nut Kit
 
This kit includes the hardware needed for all ten (10) 3/8-inch powerhead studs used on many Mercury V6 two-stroke outboards. The set includes eight (8) 3/8" stainless steel case-hardened thick washers, eight (8) stainless nuts, two (2) flat stainless washers, and two (2) jam nuts for the front two powerhead studs.
 
This hardware combination is commonly found on Mercury Racing 225 HP, 245 HP, 260 HP, 280 ROS, and 300 Drag powerheads, and it is also used across a wide range of legacy Mercury V6 applications from 1976 through 2005.
 
Chamfered washers for easier installation
The included Mercury-style thick washers are chamfered (beveled/rounded) on one side, which helps them seat correctly and makes installation and removal easier during service or rebuild work. Using the correct chamfered washer is important on powerhead stud applications because it improves fitment and helps the hardware sit properly against the mounting surfaces.
 
Fits Mercury V6 outboards from 1976–2005
This washer and nut kit fits many Mercury V6 powerhead stud applications used on 135 HP, 150 HP, 175 HP, and 200 HP outboards, as well as Mercury Racing and high-performance models. It is commonly associated with outboards using 12-inch racing midsections, 15-inch ROS midsections, 20-inch fishing / bass midsections, and 25-inch XL midsections.
 
For performance builders and Mercury Racing owners, this kit is especially relevant for 225, 245, 260, 280 ROS, and 300 Drag powerheads where correct stud hardware is important for both fit and long-term serviceability.
 
Mercury washer part numbers and cross-reference numbers
This kit is associated with Mercury washer part numbers and cross-reference numbers including:
12-70833, 12-45175, 12-F1778, 2550W23059, F1778, 45175, 70833, 856774, 12-856774, and 8M0214963
 
These numbers are useful when matching older Mercury parts diagrams, rebuild notes, or superseded hardware listings.
 
Complete hardware set for ten 3/8-inch studs
Because the kit includes the correct mix of thick chamfered washers, standard nuts, flat washers, and jam nuts, it provides the complete hardware package for all ten 3/8-inch powerhead studs on the applications listed above. This makes it a practical choice for restorations, rebuilds, and race-motor refreshes where original hardware may be worn, corroded, mismatched, or no longer available.
 
For technical support, contact Mike Hill at +1-714-697-1716 or mike@buckshotracing77.com