Yamaha Outboard F

Yamaha

Yamaha F series outboard engines: power, versions and inspection

The Yamaha F series — four-stroke outboard engines ranging from a few horsepower to several hundred, used from small boats to large catamarans. We look at power classes, shaft lengths, key features and what to check when buying a used outboard engine.

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Yamaha F series in brief

The letter F in the Yamaha name denotes a four-stroke outboard engine, and the number indicates the nominal power in horsepower (e.g., F9.9, F40, F115, F150, F250). These engines are more economical and quieter than older two-strokes, making them widely used for fishing, leisure and commercial activities.

In Lithuania, the F9.9–F20 engines are popular for small boats, and the F60–F150 for mid-sized catamarans and inflatable boats. Larger F200–F300 engines are used for more powerful catamarans and large fishing vessels.

Power classes and versions

Smaller engines (up to around F20) are often controlled by a tiller and started by hand; mid-sized (F40–F90) and large (from F115) engines have electric start, remote control and hydraulic or electric trim (power trim). Additional letters in the name denote the shaft length (S — short, L — long, X — extra long) and the control type.

Before purchasing, it's worth finding out if the engine suits your boat's transom height and which generation it is, as this affects parts availability and electronics.

Engines and key features

Yamaha F engines typically have several cylinders (from one or two small ones to six larger V-shaped ones), electronic fuel injection (in the larger ones) and cooling with either saltwater or freshwater. Most larger models come with an electronic control system and diagnostics.

Key components: water pump with impeller, thermostats, lower gearbox with propeller, oil pump, fuel system, trim mechanism, alternator and connections. The condition of the lower unit's oil indicates whether water has entered.

What to check when buying a used outboard engine

Ask to see the engine running — it should start on the first or second try, run smoothly without smoke, and have a strong water flow in the saltwater cooling system. Check the engine hours via the hour meter or control unit if available, and review the service history.

Inspect the lower unit: the oil should be clean and not milky (milky oil indicates water ingress), and the propeller should be free of significant wear. Check the trim mechanism, fuel line, anodes, transom mounts, and look for signs of corrosion. Ask for documents and verify the serial number.

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Versions and trims

Names and equipment vary by market and production year; we list the versions most commonly found in Europe.

F2.5–F20

small engines

For small boats or as a spare engine.

Often — manual start
Tiller steering
Small, easy to transport

F40–F90

mid-range engines

Popular for small boats and inflatables.

Often — electric start
Often — remote control
Often — electronic fuel injection

F115–F150

medium to high power

Versatile for small boats and larger craft.

Often — four-cylinder
Often — trim (lift) system
Often — digital control

F200–F300

high power

For larger boats and fishing vessels.

Often — V6 configuration
Often — digital control
Higher fuel consumption

Comparison of Yamaha F series

	F9.9–F20	F40–F90	F115–F150
Who it suits	For small boats	For boats and inflatables	For larger boats
Control	Manual	Manual or remote	Remote
Starting	Often manual or electric	Often electric	Electric
Price in the used market (relatively)	€	€€	€€€

Smaller boats get by with F9.9–F20, while larger boats and inflatables often need F40–F90, and the biggest vessels should consider an F115 or more powerful engine.

Pros

Reliable and economical four-stroke engines
A wide range of generations
Good Yamaha parts and service availability
Holds its value well

Cons

Prices in the used market are higher than some competitors
Some engines have complex electronics
High-performance engines are expensive to maintain

Frequently asked questions

What do the letters in the Yamaha F designation mean?

The F denotes an inline-four engine, the numbers indicate power. Additional letters (S, L, X) specify the shaft length, while others indicate the control type, such as electric start or remote control.

How to choose the shaft length?

The shaft length must match your boat's transom height. An incorrect length results in poor performance and higher fuel consumption.

What is the milky oil at the bottom?

This indicates water has entered the lower unit—often due to worn seals. Before purchasing, it's essential to identify the cause, as repairs can be costly.

Updated 2026-10-21 · Trim levels and equipment vary by market and model year — check the equipment of the specific car. · Translated automatically

Generations