The Mercury Racing Cowl Hold Down (OEM Part Number 817708) is also referred to as the race cowl bungee, latch, or strap. It plays a critical role in securing the engine cowling on high-performance Mercury outboard motors.
Specifically designed for use on Mercury Racing outboards such as the S3000, SST 120, S2000, 150 HP Pro Max, 200 Pro Max, 225 Pro Max, and 200 EFI Super Mag, the 817708 hold-down strap ensures that the cowling remains tightly fastened during operation.
These motors are typically used in Formula 1, Formula 2 tunnel hulls, and Outboard Drag Racing where vibration, water spray, and aerodynamic pressure push mechanical tolerances to their limits. Under such conditions, conventional latching systems can fail. The 817708 bungee system, however, absorbs shock loads and maintains constant tension, reducing the likelihood of cowl dislodgement mid-race.
The strap connects across the bottom of the cowling, integrating with anchor points on the lower engine pan and the cowling itself. In exploded diagrams such as those for the S3000 or SST 120 models, it is illustrated in position 12, typically accompanied by brackets (items 13 and 14) that provide firm anchor locations.
The strap's elastomeric properties allow for slight flex and return, making it ideal for withstanding the cyclic stresses generated by Mercury Racing’s high-revving 2-stroke powerheads, such as those seen in the S3000 (rated above 300 horsepower) and the SST 120 (120 horsepower).
What makes part number 817708 unique is its cross-model compatibility and consistent performance across decades of use in Mercury’s high-output product lines. Whether on the Pro Max 150 or the EFI 200 Super Mag, the bungee latch must deliver reliability in harsh marine environments.
Failures are rare but consequential—without proper cowl retention, water ingress and aerodynamic drag can compromise engine performance or even cause catastrophic failure.
Racers and technicians alike rely on this hold down strap as part of their preventative maintenance checklist, ensuring that each engine run starts with the cowl securely latched. Its design, while simple in appearance, is the product of Mercury Marine’s extensive R&D and race-proven engineering.
The part is often replaced not because of breakage, but due to weathering, UV exposure, or elongation over many heat cycles, particularly in saltwater applications.
In summary, the Mercury Racing OEM 817708 cowl hold-down is an unsung hero in the lineup of parts supporting the brand’s racing heritage. Found on powerhouse models like the S2000, SST 120, and the venerable Pro Max 150/200 EFI Super Mag, this strap is a cornerstone of race reliability and performance.
For anyone maintaining or restoring a Mercury Racing outboard, ensuring the integrity of this unique to Mercury part is a must.
Contact Mike at 714-697-1716 or mike@buckshotracing77.com for technical support