Mercury 25HP MH FourStroke Outboard

The Mercury 25HP MH FourStroke is a manual-start outboard on a 15 inch short shaft with tiller steering, built around the 25 horsepower range's three-cylinder four-stroke block, without an electric starter to carry.

What it's for

Mercury positions this engine for aluminum tiller boats, jon boats, utility hulls, and fish-and-ski setups, where a lighter, simpler motor pays off more than an electric starter would. Electronic fuel injection still gives quick, reliable starts on the pull cord, and the cylinder head is tuned for crisp throttle response.

Construction and protection

Mercury lists this motor as saltwater rated, with zinc-coated components for corrosion resistance in fresh and salt water, wet sump lubrication, and thermostat-controlled water cooling. Gear shift runs forward, neutral, and reverse, tilt is manual, and recommended fuel is 87 octane unleaded gasoline with up to 10 percent ethanol. Mercury notes smooth, quiet, low-vibration running, with low oil pressure and overheat warnings built in as standard protection.

What's included

The crate holds a 6.6 gallon tank with quick-connect line, mounting hardware, an owner's manual, and a tool kit, plus Mercury's 3-year warranty. The propeller must be purchased separately to match your boat.

Does the MH have electric start? No, it starts manually; EFI is there for quick starts rather than push-button convenience. What boats suit it? Mercury lists aluminum tiller, jon, utility, and small fishing boats.

Specifications