The Horn Lid / Cap is designed to fit all Mercury Racing 2.5L EFI air horn inlets and horns, giving your high-performance outboard the protection it never came with from the factory. Each kit includes one (1) USA-made horn lid in your choice of color and one (1) extra Mercury round decal so you can keep your race-ready look clean and professional.
 
Most Mercury Racing 2.5 EFI outboard motors do not use traditional air cleaners or air filters on the air horn. Instead, they rely on open airflow under the cowling for maximum power and throttle response. This setup works well on the water, where the engine is exposed mainly to air and spray, but it leaves the intake vulnerable when the boat is on the trailer, in the shop, or in storage.
 
From the factory, outboards are engineered for a marine environment where water and spray are more common than dust and sand. Adding a conventional air filter in this setting could trap moisture and restrict airflow, which is not ideal for a high-performance two-stroke.
 
At the same time, these engines depend on a large volume of unrestricted air to support combustion and cooling at high RPM. Any restriction at the air horn can reduce performance, especially under heavy load or at wide-open throttle.
 
To manage this, outboards use cowlings and intake design to help deflect larger debris while running, but the air horn itself remains open. When the engine is not in operation, that open horn becomes a direct path for dust, dirt, sand, moisture, insects, or shop debris to enter. Over time, this contamination can lead to premature wear or serious engine damage.
 
Installing a Horn Lid / Cap on your Mercury 2.5L EFI air horn during trailering, storage, or maintenance provides a simple but highly effective layer of protection. The lid helps keep dust and grit out of the intake, reduces the risk of moisture and corrosion, and shields the horn from overspray or debris in the shop.
 
It turns a wide-open intake into a sealed, protected area until you are ready to run the engine again. When it’s time to hit the water, you simply remove the lid, fire up the motor, and enjoy full, unrestricted airflow.
 
These plastic horn lids are made in the USA and engineered to fit popular Mercury Racing outboard models, including the Mercury 260 HP, Mercury 280 ROS, Mercury 300 Drag, and Mercury S3000.
 
They are designed to work with Mercury air inlet horn part numbers 816058T12 and 13256A2, covering the most common Mercury Racing 2.5 EFI air horn configurations used on performance and race boats.
 
If you run a Mercury Racing 2.5L EFI—whether it’s a 260, 280 ROS, 300 Drag, or S3000—the Horn Lid / Cap is an inexpensive, smart upgrade that helps protect your investment. By keeping the air horn clean and free from contaminants when the engine is off, you help ensure that your race motor stays ready to perform every time you turn the key.
 
Each kit includes one (1) LID/CAP (your choice of color) with a Mercury DECAL and one (1) extra round Mercury DECAL.
 
For technical support, contact Mike Hill at +1-714-697-1716 or mike@buckshotracing77.com