In Mercury’s legacy 2-stroke lineup of high-displacement outboard motors, the connecting rod bolt plays a vital role in engine durability and performance. These bolts must withstand significant cyclical loading, particularly in high-RPM conditions common to the 3.0-liter V6 Carb, EFI, DFI, and Optimax platforms.
The 3.0 and 3.2-liter Rod Bolt from Buckshot Racing #77 is a high-strength, precision-engineered fastener designed as a direct replacement for Mercury OEM rod bolt part numbers 43813 and 94320. While we are not the manufacturer of this bolt, we offer it as a reliable, performance-oriented solution for engine builders and marine technicians working on Mercury 3.0L powerheads.
The Buckshot # 77 bolt is engineered to fit a wide range of Mercury 3.0-liter Carb and EFI V6 outboards. These include standard production models such as the 200 EFI, 225 EFI, and 250 EFI, along with advanced variants like the 225 DTS, 250 Pro XS, and 250XB. It also fits high-performance platforms including the 300 EFI, 300 SuperMagnum, 300 Pro Max, 300X, and 300XS.
Additionally, this bolt is compatible with certain L3 and L4 3.0L inline configurations, which share internal geometry with the V6 architecture. Across all these engines, the connecting rod and cap design remains consistent, making our Rod Bolt a precise fit for applications originally equipped with Mercury bolts 43813 or 94320.
Buckshot Racing’s No. 77 bolt is manufactured from a high-tensile alloy steel designed for fatigue resistance and dimensional stability under thermal cycling. Unlike Mercury’s original torque-to-yield bolts, which require a complex torque-plus-angle method, the Buckshot bolt simplifies installation without compromising clamping force or mechanical reliability.
This bolt is especially appropriate for engines operating under elevated stress, such as performance builds or outboards used in racing and commercial duty cycles. Its design is intended to reduce bolt stretch, maintain cap alignment, and improve service life when compared to reused OEM hardware.
The installation process for the Buckshot No. 77 bolt is straightforward and tailored for precision and repeatability:
Torque Specification: Tighten each bolt to 30 ft-lbs with no additional angle turn required.
Threadlocker: Apply a dot of RED Loctite 271 or an equivalent red high-strength threadlocker to the cleaned and dried threads before installation.
Tooling: Always use a calibrated torque wrench for accurate torque values.
Curing: Allow an appropriate curing environment for the threadlocker during installation.
Proper installation technique is essential to avoid bolt failure or cap fretting. Reusing rod bolts is not recommended, as they may experience permanent elongation after their initial torque cycle.
The Buckshot No. 77 is a direct-fit replacement for the following Mercury rod bolt part numbers 43813 (original OEM part) and 94320 (later supersession).
These bolts are found across the majority of Mercury’s 3.0L EFI lineup, with identical form, thread pitch, and shoulder dimensions. The Buckshot bolt adheres to the same physical specifications while offering improved performance attributes.
Rod bolt replacement is a standard procedure during any engine rebuild, particularly in high-output applications. The Mercury 3.0L EFI V6 family—including models like the 300X, 300XS, and 250 Pro XS—routinely operates near or above 6,000 RPM, placing increased demands on fastener integrity. Even engines in moderate-use scenarios, such as the 225 EFI or 300 Pro Max, benefit from upgraded hardware during overhaul.
The Buckshot No. 77 bolt is suitable for all of these applications, as well as, for remanufactured L3/L4 3.0L industrial or marine engines, where reliability under load is critical.
The Buckshot Racing Rod Bolt #77 is a direct replacement for Mercury 43813 and 94320 bolts, offering improved mechanical properties and a simplified installation process for Mercury’s entire 3.0L family.
We provide this bolt as a dependable option for technicians and builders seeking long-term reliability, consistent torque retention, and compatibility across a wide range of Mercury engines—from standard 200 EFI configurations to top-tier 300XS powerheads.
Includes twelve (12) Rod Bolts, Replaces Mercury 94320
For technical support, contact Mike Hill at +1-714-697-1716 or mike@buckshotracing77.com