Suzuki 140 Outboard Problems: 5 Most-Common Issues

Suzuki Marine’s DF140A is a popular choice of outboard engine for those looking for a lightweight motor without compromising on performance. In addition, the DF140A is equipped with Suzuki’s advanced Lean Burn Fuel Control System, which means that this engine offers great fuel economy without having to hold back on your speed.

This 4 cylinder outboard has also been designed to use aggressive gear ratios that enables these outboards to turn a larger propellor which also increases performance. It’s no wonder that this engine was one of the ones chosen for use at the London Olympic & Paralympic Games Sailing Regatta back in 2012.

However, like with any brand, there are some common problems to look out for.

In this article, we take a look at what those common problems are:

1. Faulty ECU’s (Electric Control Units)

Modern outboard engines share technology with car engines, and an electronic control unit is just one example.

The Electronic Control Unit, or ECU, manages an engine’s timing, the fuel/air mixture, and the spark. So if the ECU is faulty, your outboard engine will either fail to start, or the engine will cut out when idling or lowering the revs.

There are several reports on the Suzuki Forums about faulty Electronic Control Units, and it is an expensive part to replace. However, the good news is that the ECU on an outboard engine can often be repaired or reprogrammed to eliminate the fault.

2. Interior Rust Or Corrosion

While Suzuki has developed an advanced anti-corrosion system which has earned Suzuki outboard engines a good reputation for reliability, durability, and corrosion resistance, there are still some issues with interior rust or corrosion.

This is especially true when an engine is not flushed properly after each use.

Unfortunately, corrosion is a common problem across all outboard engines brands, particularly those used in saltwater. An outboard engines’ anodes help protect against corrosion, but it’s a good idea to check you have the correct ones.

Saltwater anodes are supposed to be zinc, and freshwater anodes a magnesium alloy. These anodes are your first line of defense against corrosion as they will corrode before other metals inside your engine.

In addition, the Suzuki DF140A from 1999 – 2008 is known to have a corrosion problem on a plug located on the engine holder’s port side. It was originally designed for an oxygen sensor that never materialized.

The main problem is that the engine holder is aluminum, but the plug is steel: these two different metals touch and causes corrosion from the inside out. If left unchecked, the plug will erode through the engine holder and blow out the side, or worse, blow internally, causing even more damage.

Unfortunately, Suzuki never admitted to this design fault, and their warranty does not cover rust or corrosion.

3. Issues With The Idle Air Control Valve (IAC)

The Idle Air Control valve or IAC helps an outboard engine maintain idling speed by controlling the amount of air coming into the engine.

If your engine has trouble idling or starts but keeps stalling, you may have a malfunctioning IAC valve. While this seems to be a fairly common problem with Suzuki outboards, the good news is that it is easy to diagnose, the repair takes approximately 15 mins (even in the water), and the replacement part isn’t too expensive.

Alternatively, you can try simply cleaning the valve as sometimes there is a build-up of dirt from the air pollution that needs wiping away.

4. Grinding Noise On Engine Tilt/Trim

While this grinding noise when the engine is on tilt or trim may sound nasty, it normally causes no actual damage and indicates that the tilt rods need lubricating.

Boaters can apply a small amount of grease to the rods where they touch the engine to solve the problem.

5. Excess Vibration & Noise

Some people complain about excess vibrations and noise from their Suzuki 140 outboard engine. But excess vibrations and noise are very uncommon with the new engines of today.

If you are experiencing excess vibrations and noise, it could be down to the installation. Check that the engine is mounted correctly – even the correct height is important.

Also, check for any damage to the propellor or even to the propellor shaft – if the boat has accidentally grounded or hit something, the shaft or the prop may be out of alignment, which will cause excessive vibrations and noise.

General Pros & Cons Of A Suzuki 140 Outboard Engine

Suzuki has been making outboard engines since 1965, and while they may not be as popular as some of the other well-known brands, they have their fans.

The Pros:

The Suzuki DF140A is a very popular outboard as it is light and compact while still providing exceptional performance. Suzuki Marine boasts that this motor has the best power-to-weight ratio in its class. In addition, the design of the engine cover has a large air induction opening to provide maximum airflow, which creates maximum power. It’s also the first 4-stroke to utilize an oil cooler, which ensures that 140hp is available in any condition.

The Suzuki DF140A provides reliable, heavy-duty performance with long-lasting durability, all in a lightweight package.

Other features include:

  • Lean Burn Fuel Control – this technology provides great fuel economy without sacrificing outboard engine performance.
  • Converting Power Into Speed – Suzuki has designed their in-line four-cylinder outboards to use aggressive gear ratios that allow these outboards to turn a larger propellor. The combination of a larger propellor and smaller gear ratio helps to deliver plenty of torque, creating faster acceleration and improved top-end speeds.
  • O2 Sensor Feedback System helps keep emissions cleaner and more stable, contributing to a cleaner environment and adhering to strict emission controls in various countries around the world.

The Cons:

  • Faulty ECU’s (Electric Control Units)
  • Interior Rust Or Corrosion
  • Issues With The Idle Air Control Valve (IAC)
  • Grinding Noise On Engine Tilt/Trim
  • Excessive Vibrations & Noise

Final Thoughts

Prices for a new Suzuki 140 outboard engine start at around $10,000, a very competitive price.

Of course, you can find cheaper second-hand – the more hours on the engine, the cheaper it will become. Suzuki offers an affordable and reliable alternative to other more popular brands out there.

Suzuki isn’t as well-known as Yamaha, but those who’ve used or owned these engines swear by them. With regular maintenance and care, it’s not unusual to hear that these motors can last many thousands of hours.


Suzuki DF140A

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