Yamaha 150 Outboard Problems? 5 Most-Common Issues

Yamaha is a Japanese company that started developing and building outboard motors in 1958.

They first entered the US market in 1970, where they quickly established themselves as an industry leader by offering both reliability and service that was second to none.

Nowadays, Yamaha offers a range of both 2-stroke and 4-stroke engines ranging from 2hp to 350hp:

About The Yamaha 150 Outboard Engine:

Yamaha Marine released its new F150 four-stroke outboard engine to the market in 2004.

This 150hp engine was designed to satisfy the needs of the recreational boating community looking for a quieter engine with fuel-efficient power for small to mid-sized boats.

The Yamaha F150 quickly became one of the most popular engines around, with Yamaha themselves boasting that it is “the best-selling 150hp four-stroke engine of all time.”

Yamaha Marine has been a leader in the business of developing and building outboard motors for many years. They have a reputation for building one of the most reliable outboard engines on the market.

However, just like with any other boat engine manufacturer, problems do arise.

The following are the 5 most common problems with Yamaha 150 outboard engines to look out for:

1. Failure Issues With The Harmonic Balancer (HB)

The Harmonic Balancer or HB is a part of the engine that acts as a shock absorber to remove any unwanted vibration caused by the crank-shaft movement within your engine.

If the Hamonic Balancer fails, your outboard engine will begin to vibrate excessively, which can cause internal damage to your engine.

This problem seems to be more associated with the older, 2004, and 2005 models. As soon as Yamaha became aware of the problem, they modified the design of this component.

While the new design is more reliable, some users still complain about the Harmonic Balancer failing in later models.

Symptoms to look out for a failed Harmonic Balancer include excessive engine vibrations, hearing a high-pitched whine, seeing misaligned timing marks, and belts falling off.

If you suspect your Harmonic Balancer is failing, contact your Yamaha dealer and have your engine inspected by a professional.

2. Faulty Exhaust Components

Yamaha 150 outboard engine owners have complained about severe corrosion and pitting in their exhaust systems, leading to premature engine failure.

It is believed that this corrosion is caused by a manufacturing or design defect relating to the coating used for the exhaust components.

This problem coating affected earlier models and allowed hot exhaust fumes to corrode the exhaust pipes instead of preventing this corrosion. This corrosion can lead to holes in the exhaust system, which can eventually cause horsepower, smoking, and engine failure.

The main problem with this type of corrosion is that it can go unnoticed for many years. Hence the 3 year warranty period that Yamaha offers is often up before the customer notices this defect.

When Yamaha became aware of this design defect, they created a kit that affected owners could buy.

However, most affected owners complain that these kits are expensive.

3. Fuel Systems

Today’s modern fuel systems can be trickier than ever before.

One of the first steps to maintaining a good fuel supply with the Yamaha 150hp outboard engines is to install an external Yamaha 10-micron fuel and water separating filter as the manufacturer recommends. This filter doesn’t come as standard.

It is also recommended to add a fuel stabilizer to the fuel tank every time you fill up with fuel. Fuel stabilizers are preventive treatments for your outboard engine.

These fuel stabilizers will help stop chemical reactions or fuel instability, usually caused by bad or old fuel.

When added to new marine fuel at its peak of quality, a fuel stabilizer will help keep it that way. In addition, always try to buy fresh fuel from a busy gas supplier and sell it.

This means that it isn’t stored in commercial underground tanks for a long duration. Old fuel means it is more susceptible to contamination.

4. Corrosion Due To Saltwater

A big problem with any outboard engine, and not just Yamaha, is the damage caused by using your boat in saltwater without flushing with fresh water after each use.

If your engine is not properly rinsed, the salt builds up and causes corrosion (such as the anodes melting away).

A build-up of salt will clog passages and get into places it doesn’t belong, and then you may be left with serious damage to your engine and a major repair bill.

To prevent the corrosion of the metal components of your outboard engine, you need to rinse the metal completely with fresh water after taking your boat out of the saltwater.

Afterward, you can leave the engine to dry out thoroughly, but pay attention to rinsing out those hard-to-reach corners and pockets where saltwater can gather. To store an engine that regularly sits in saltwater, treat the engine with a fine layer of oil, antifreeze, or kerosene.

These measures can keep boat outboard engines and other seafaring metals from corroding and prolong their lifespan.

5. Problems Starting

Having difficulties starting is a relatively common problem and has many potential causes.

The first thing to check is that you have enough fuel!

Another common problem is to make sure that your battery is not dead. If your battery seems dead at the start of a day and you have a battery selector switch, make sure it’s turned to the ‘on’ position before trying to switch on your engine.

Some boats have an electrical main switch for their batteries, which may have been set to the “off” position by mechanics or others who know that boat lights or a pump can accidentally be left on, which can drain your battery.

Another obvious fault is that an ignition switch or the wiring can become loose. This can be quickly remedied by checking connections or tightening screws that hold it in place to make sure you have proper electrical contact.

Also, make sure your boat’s motor throttle is neutral. Sometimes a throttle is accidentally bumped from the neutral position, which means the engine won’t start.

If these simple remedies don’t work, you may have a more complex problem involving contacting a marine mechanic or your local Yamaha dealer.

General Pros & Cons Of A Yamaha 150HP Outboard Engine

While Yamaha started as a manufacturer of musical instruments and then motorbikes, they have developed and manufactured outboard engines since 1958.

Because of their innovation and attention to detail, such as offering good service, they have become one of the top manufacturers of outboard motors.

While we have looked at the 5 problems to look out for with a Yamaha 150hp outboard engine, these motors have many pros:


Yamaha launched its first 150hp four-stroke outboard motor in 2004 and was one of the first brands to meet the new emission control laws.

It was also one of the first to offer a quiet and fuel-efficient option for medium-sized fishing and recreational boats.

This outboard weighs only 478lbs, or just under 217kg (for the 20-inch shaft models), and has a more stream-lined width than the two-stroke motor equivalent.

The F150 is a great option for a single-engine on smaller 17 to 22 feet boats or a twin installation on 23 to 27-foot boats. Plus, users can install this engine on most, if not all, models of boats.

The F150 outboard engine was the first and is now a part of a bigger family line, including the F175 and F200. These motors are now compatible with both digital or mechanical rigging controls.

This new design had some initial faults, but the Yamaha F150 outboards produced after 2005 are often considered “one of the most reliable four-stroke outboards ever produced.”


  • Failure Issues With The Harmonic Balancer (HB);
  • Faulty Exhaust Components;
  • Fuel Systems;
  • Corrosion Due To Saltwater;
  • Problems Starting.

Final Thoughts

The question of which engine will be the right choice for you and the boat you’re looking at is a question for which there is no right answer.

Every boat and the owner will have different requirements, but we can say one thing with certainty –  we don’t think you can go wrong if you choose a Yamaha F150 outboard engine.



What Does A Harmonic Balancer Do?

Troubleshooting Your Yamaha 4-Stroke Motor

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