Boat owners restoring or repowering Mercury outboards built before the SmartCraft and DTS era now have a trusted OEM solution: the Mercury 816626A20 and 816626A25 wiring harness kits, offered by Buckshot Racing #77. These harness assemblies are designed specifically for legacy Mercury, Mariner, Quicksilver, and Force engines using the 8-pin engine-side connector—a standard used on Mercury powerheads from 1976 through 2005.
 
Each kit is 100% genuine OEM Mercury, not aftermarket or universal-fit. That means everything from the factory 8-pin connector to the OEM key switch, overheat warning horn, and trim/tilt wiring with original Mercury connectors is engineered to fit and function exactly as it did from the factory.
 
You also get OEM dash-mounting hardware, radius zip-ties, and model-specific installation instructions that walk you through wiring for every engine type from 40 HP to 300 Drag, including two-stroke, Optimax, Black Max, and FourStroke models up to 225 HP.
 
You can choose between two lengths: the 816626A20 features a 20-foot harness ideal for smaller vessels or near-transom consoles, while the 816626A25 offers a 25-foot harness for boats requiring extended reach to the helm.
 
Both options are plug-and-play for 8-pin Mercury systems, preserving critical functionality like trim and tilt, overheat protection, and engine ignition—without the need for splicing or adapters.
 
It’s important to note that these kits are not compatible out of the box with newer Mercury engines that use the 14-pin engine harness, which Mercury began introducing around the 2006 model year. These newer 14-pin systems are standard on modern SmartCraft-equipped and Digital Throttle & Shift (DTS) motors.
 
However, if you're installing this 8-pin control harness on a newer engine that uses the 14-pin connector, Buckshot Racing #77 also offers a 14-pin-to-8-pin adapter, available for separate purchase. This adapter bridges the two harness styles, allowing boaters to retain the OEM control side wiring while connecting to a modern 14-pin Mercury engine.
 
That makes these kits from Buckshot Racing #77 a perfect fit not only for full OEM restorations of vintage and mid-generation Mercury outboards, but also for transitional setups where an older boat is being paired with a newer motor. Whether you're working with a classic 150 HP Black Max, a 200 HP Optimax, or even a Force 120 HP model, the 816626A20 and 816626A25 kits provide an authentic, factory-correct installation path.
 
Select the Mercury 816626A20 (20 ft) or 816626A25 (25 ft) after measuring the boat dash to the engine harness path length.
 
Contact Mike Hill at mike@buckshotracing77.com w/ technical questions