2025 Mercury Marine® FourStroke 9.9hp EFI Base

2025 Mercury Marine® FourStroke 9.9hp EFI

Mercury FourStroke outboards are made to unlock the inaccessible. To make light work of long journeys. The 2.5 to 20hp FourStroke outboards empower you to enjoy the water on your terms and reach places you wouldn’t dare venture with other engines. They’re reliable, compact, lightweight, easy to install and simple to operate, while still delivering quick acceleration and impressive speed. The only thing missing is a destination.

Features may include:

Electronic Fuel Injection (EFI)

From the moment you crank the engine to the moment you drop the throttle, EFI technology (on 8 to 20hp outboards) responds with instant power. Surefire starting in all weather conditions. Smooth, efficient acceleration. Maximum fun.

Battery-Free EFI

Go farther confidently with battery-free EFI technology, included with manual-start 8 to 20hp outboards. It lets you enjoy the flexibility of portability, without needing to bring along a cranking battery.

Convenient Maintenance

We made maintenance easier with features like a no-spill oil change system, easy-out fuel filter and lifetime maintenance-free valve train

Advanced Tiller

With a range of adjustments, easy-to-reach controls and the flexibility to be set up for left- or right-handed operation (on select models), Mercury tiller handles put you in complete command of your adventures.

Easy Portability

Simple to install and lightweight, 2.5 to 20hp FourStroke outboards let you bring along the fun wherever it’s needed.