2020 Yamaha 4 HP F4LMHA Outboard Motor

The 2020 Yamaha F4LMHA is a 4 hp, single-cylinder four-stroke portable on the long, 20-inch shaft, manual-started, built around a compact 139cc engine rated at 4hp at 4500rpm. At 61 pounds it suits small dinghies and tenders where a taller transom and easy carrying both matter.

Why long shaft here

This is the 20-inch version, meant for a taller transom than Yamaha's short-shaft 15-inch F4 sibling; mounting it on a lower transom would leave the motor sitting too deep. Starting is manual pull-cord only, so there's no battery or wiring to install.

Under the cowling

Bore and stroke measure 62 by 46mm, compression runs at an 8.9:1 ratio, and the overhead-valve design revs through a 4000-5000rpm full-throttle band. Cooling is water-based with thermostatic control, lubrication is wet sump, and trim adjusts across five positions with up to 69 degrees of tilt.

Upkeep

Yamaha specifies regular unleaded fuel at a minimum 87 octane, Yamalube 4M oil at a .6L fill, spark plug CR6HSB, a 17mm prop nut, and an 8mm fuel hose.

Carrying it around

A motor this size gets moved by hand far more often than a bigger outboard ever does, so drain the carburetor float bowl before laying it on its side in a car trunk or storage locker, rather than assuming a sealed cap keeps fuel from seeping out.

Common questions

Does it need a battery? No, starting is manual pull-cord only, and this unit is sold new.