The Mercury 25hp EFI (25MH) delivers top-tier performance in a lightweight, portable package. Engineered with a revolutionary battery-free Electronic Fuel Injection (EFI) system, this 500cc 3-cylinder engine ensures fast, reliable manual starting and industry-leading fuel efficiency. With its 15-inch short shaft and advanced multi-function tiller handle, the 25MH is the premier choice for aluminum fishing boats, soft-bottom inflatables, and utility skiffs that require punchy acceleration and smooth operation.
Technical Specifications
| Model Number / MPN |
25MH |
| Horsepower |
25 HP (18.6 kW) |
| Shaft Length |
15 Inches (Short Shaft) |
| Engine Type |
Inline 3-Cylinder / 4-Stroke SOHC |
| Displacement |
500 cc (30.5 cubic inches) |
| Starting System |
Manual Recoil Start (EFI) |
| Full Throttle RPM |
5400 - 5800 RPM |
| Dry Weight |
Approx. 132 lbs (60 kg) |
Powerfully Smooth, Incredibly Efficient
- Battery-Free EFI: Provides instant starting and crisp throttle response without the need for a cranking battery, reducing boat weight.
- 3-Cylinder Design: Offers superior balance and lower vibration compared to 2-cylinder models, resulting in a quieter, smoother ride.
- Multi-Function Tiller: Features shifting, throttle control (with friction adjustment), and stop button integration for intuitive one-handed operation.
- Maintenance-Free Valve Train: Eliminates the need for periodic valve adjustments, significantly lowering the total cost of ownership.
- 6 Trim Positions: Includes shallow-water drive settings to allow safe navigation in restricted and shallow waterways.
Professional Reliability for Your Transom
The Mercury 25hp EFI is built to outwork and outlast. Its high-displacement 3-cylinder powerhead provides the torque necessary to get on plane quickly, even with a heavy load. Protected by Mercury’s industry-leading 4-Front Corrosion system and featuring robust stainless steel internal components, this engine is designed to excel in both fresh and saltwater. Whether you are a professional guide or a weekend explorer, the 25MH delivers the legendary Mercury performance you can trust.
Frequently Asked Questions
1. Is an external battery needed to run the EFI?
No. The 25MH features a "battery-free" EFI system that generates its own power for the injectors and sensors during the first pull of the manual recoil.
2. Does it include a fuel tank?
Yes. This unit comes standard with a 6.6-gallon (25L) external fuel tank and a high-quality fuel line with quick-connect fittings.
Marine Equipment Specialist | Genuine Provider | Genuine Mercury Parts & Accessories
