2017 Yamaha F4 SMHA Outboard Motor

Yamaha's 2017 F4 SMHA is the short-shaft (S=15 inch) counterpart to the L-shaft F4, built around the same single-cylinder, 139 cc four-stroke block but at a 60 lb dry weight. It suits a lower transom than the 20-inch version, so shaft length is the detail to confirm first.

Mounting and control

A long-span mounting system and a dynamically balanced crankshaft keep vibration in check regardless of shaft length. The helm turns 90 degrees from straight ahead in either direction, and the trim has 5 steps running up to a 69-degree tilt, with a built-in fuel filter sitting ahead of the carburetor.

Durability details

This is a manual-start, carbureted motor with a CDI ignition. Minimum pump octane is 87 on regular unleaded, and oil capacity lands near six-tenths of a liter. Compression is 8.9:1, exhaust routes above the propeller, and a five-step anti-corrosion paint process with sacrificial anodes protects the block, with ethanol content capped at 10 percent.

Is it electric start? No, this is a manual-start motor as noted above, with no battery to maintain. How is it cooled? Water cooling with thermostatic control, needing no manual adjustment once it is running. Does the 15-inch shaft fit any transom? No, confirm the transom height against the 15-inch figure before ordering; it is not interchangeable with the 20-inch F4LMHA.