2017 Yamaha F4 LMHA Outboard Motor

Yamaha's 2017 F4 LMHA is the long-shaft (L=20 inch) version of its smallest four-stroke portable, rated at 4 hp from a single 139 cc cylinder. At 62 lbs dry, it moves easily between boats while a pressurized lubrication system, rather than simple splash lubrication, keeps internal wear down over time.

Choosing the right one

The 20-inch L shaft wants a taller transom than Yamaha's short-shaft F4, so measure before ordering rather than guessing. Steering swings 90 degrees off-center in either direction, and tilt reaches 69 degrees over 5 trim positions, with the exhaust routed above the propeller and a long-span mounting system keeping vibration in check.

Running and maintenance

A CDI ignition and a CR6HSB spark plug keep this manual-start, carbureted motor straightforward. It runs on regular unleaded gasoline rated at least 87 octane, and the crankcase holds close to six-tenths of a liter of oil. A five-step anti-corrosion paint finish and sacrificial anodes guard the block for saltwater duty, with stainless hardware used throughout the drive train beneath that coating. Compression sits at 8.9:1, and a built-in fuel filter sits ahead of the carburetor.

Will it run on ethanol-blended fuel? Yamaha caps ethanol content at 10 percent. Is cooling automatic? Yes, water cooling with thermostatic control, with no adjustment needed once it is running. Is there a charging option? Only with an optional kit that adds a 6-amp alternator for small electronics.