Yamaha F4BMHS/L

Yamaha F4BMHS/L Outboard: The Ultra-Light 4HP Backup Every Tender Needs

Dinghies don’t need much. A few horsepower, something light enough to hang off the transom without throwing off trim, and an engine that starts when your hands are cold and your patience is short. The Yamaha F4BMHS/L was built around exactly that brief. It’s small. It’s simple. And it just works.

What’s Actually Under the Cowling

Strip away the marketing and you’re left with a 4-stroke, single-cylinder OHV engine displacing 139cc, tuned specifically for auxiliary duty rather than raw speed. The Yamaha F4BMHS/L horsepower rating sits at a modest but entirely sufficient 4HP, enough to push a loaded inflatable tender at a respectable clip or nudge a small sailboat off a dock when the wind won’t cooperate. Nobody buys this motor to go fast. They buy it because it starts, every time, without drama.

Yamaha F4BMHS/L Specs Worth Knowing

Weight is where this engine earns its keep. At roughly 27 kg, or about 59 lbs, it’s light enough for one person to lift off a transom bracket and stow below deck without a winch or a second set of hands. An ergonomic carrying handle makes that lift genuinely comfortable, not just technically possible, and the 3-position leak-free storage design means you can lay it flat in a lazarette or a truck bed without fuel weeping into the bilge. That last detail matters more than it sounds like it should. Anyone who’s cleaned gasoline residue out of a storage locker knows exactly why.

Fuel comes from an integrated 1.1-liter tank built right into the cowling, small enough to disappear visually but large enough for a solid afternoon of puttering between anchorages. When longer range matters, an external tank connection is available, letting you swap to a bigger reserve without touching the internals. CDI ignition handles the spark side of things, and it’s a big part of why pull starts on this engine feel almost too easy. No battery to charge, no choke sequence to memorize. Pull the cord, and it fires.

Two Shaft Lengths, One Reliable Engine

Transom height varies wildly across tenders, dinghies, and small skiffs, so Yamaha offers the F4BMHS/L in two configurations. The “S” model is built for 15-inch transoms, the more common spec on compact inflatables and small hard-shell dinghies. The “L” model steps up to fit 20-inch transoms, which tends to suit larger tenders and some small sailboats where the engine sits further from the waterline. Measure your transom before ordering. It’s a five-minute check that saves a return shipment later.

Every unit ships with the full Yamaha F4BMHS/L manual, covering break-in procedure, fuel mixture guidance, and the maintenance intervals that keep a small engine like this running for decades rather than seasons. Owners of these little four-strokes routinely report a decade or more of dependable service, provided the basics get done on schedule.

Weighing the Investment

Compared to what a dead motor costs you mid-trip, stranded, paddling, or waiting on a tow, the Yamaha F4BMHS/L price looks like cheap insurance. This is the auxiliary engine you buy once and stop thinking about, the kind of purchase that quietly earns its keep every single time conditions turn.

Ready to Order

Confirm your transom height, choose between the S and L shaft options, and click Add to Cart. Marine Gear Depot has the Yamaha F4BMHS/L in stock and ready to ship, ready to be the small engine that never lets you down when it matters most.