6 Most Common Problems with Suzuki 140 Outboard

Out of all its 4-strokes, Suzuki 140 is probably the most interesting one. The engine owns the most alluring power-to-weight ratio. Delivering 140 HP from its mear 410-pound body.

Suzuki 140 is an extension of the DF115A engines by the same company. Therefore, the engine carries dual overhead camshafts, 4 valved cylinders, and the Lean Burn technology.

Suzuki has been wowing boaters since 1965 with its outboards. The 140 HP is no less of a product by Suzuki. Yet owners have had some common complaints over the years.

In this article, I will discuss the most common problems with the Suzuki 140 outboard.

6 Common Suzuki 140 Outboard Problems:

1. Engine Running Rough At Idle:

At low RPMs, the engine seems to run ‘rough’. You may also call it ‘the engine missing’.

Customers reported the engine ‘kicking’ once they go anywhere approaching 1500-2000 RPMs. The engine will run on all 4 cylinders but will be ‘kicking’ or roughing.

This problem does not happen much when the engine is cold. Moreover, throttling is easier from idle too after the kicking. At lower revs, the problem exaggerates. Even to the point that it’s impossible to control the boat.

Usually, there is a problem with the plugs connecting the cylinders. A bad thermostat may also cause such roughing at idle.

Sometimes, after roughing, the engine refuses to pick up the RPMs. You may find cylinders dying out or injectors failing to be the cause.

In most cases, users find problems with cylinder number 4. The least severe and most common symptom is the blackening of the cylinder. This pattern suggests design issues by Suzuki.

2. O2 Sensors Failing/Faulty ECM: 

When oxygen sensors fail, you get a check engine sign. A code 3-6 is sent to you often due to a faulty sensor.

This problem seems to be fairly common in Suzuki 140 outboards. On average, at least 3 sensors fail per person.

Moreover, the ECM may be failing. When the ECM fails, it generates signals that suggest the oxygen sensor failing.

Back when these engines first launched, the ECM problem was pretty common. Replacing the oxygen sensor with the newer version may eliminate these problems.

3. IAC Valve Issues:

Problems with the IAC valve generally manifest as the engine not starting. That is it does not start at all.

Other times, the engine does not push to higher RPMs. For example, it would not go above 3000 RPM. When brought to idle, it would display an error code. Probably 3-1 error code.

The 3-1 error code denotes the IAC valve screw adjustment issue. It is also known as the By-pass air screw adjustment issue.

Another symptom is the engine shutting off at idle. However, this can be a symptom for many reasons. Including spark plug failure, fuel pump issue or any corrosion issue.

Faulty IAC valve, corrosion, kinks may lead to the failure of the valve. The IAC valve failure is pretty common in Suzuki 140 outboards.

4. Corrosion Issues:

This is one of the most common problems generally in Suzuki outboards.  Common manifestation of the issue is the engine stalling at neutral. After stalling, it fails to idle.

Corrosion occurs due to rusting. The most crucial part of rusting is the engine mount. It greatly affects the trimming of the boat. Rusting occurs in the port of the mount and damages the mounting position.

Sometimes the exhaust gets trapped because of a bad design. This causes corrosion and exhaust leaks. Exhaust leaks can be found on the steel plugs of the engine block.

The anodes get corroded as well. You need to keep track of freshwater (magnesium alloy) and saltwater (zinc alloy) anodes.

Corrosion may also occur on latches on the cover of the motor and hose clamps.

5. Clattering Noise at Tilt/Trim:

At tilt, the boat may make clattering noises. The noise may sound like more of a sticking noise. This may come with no visible signs of damage.

The most common reason is lack of lubrication. The ends of the rams make contact with the engine. The end of tilt rods making contact also produces noise. A bit of lubrication benefits the issue.

At low RPM, if the gear rattles, it may be because of the stainless prop. The tilt/trim solenoids may also be the issue (rattling from cowling).

6. Faulty Starter Motor:

Although this is less reported, the issue is quite common. Due to a faulty starter motor, starting and restarting the engine becomes a problem.

Most of the time, the problem is thought to be in the battery, fuel pump, etc. Especially in new boats, this issue is common.

Not only the starter battery but the battery cables can be a problem too. Corrosion leads to damage to the cables, rendering them faulty.

What Majority of the Users Feel About Suzuki 140 Outboards?

The Suzuki 140 motors are loved by most customers. They are good 4-stroke engines. The lesser weight with more power deliverance is appreciated by everyone.

It also comes with stingy fuel consumption. Adding to good fuel economy. Suzuki’s lean burn technology is responsible for mixing the maximum amount of air with minimum fuel. That is the air to fuel ratio is less.

Corrosion is bad finance for boaters everywhere. Suzuki outboards seem to be standing out in this problem. It gets quite expensive to fix too.

However, a bit of corrosion is expected in all engines after certain hours on it. The Suzuki corrosion problem is no different.

The 2021 Suzuki DF140ATX – Black costs $ 15,595. A used outboard can be found at about 30% cheaper rates. The rate reduces with hours increasing on the outboard.

Final Thoughts

To sum up, Suzuki has been one of the favorite outboards by many boaters. The 140, in particular, is the most favored by boaters. The 4 into 2 into 1 exhaust system supports a boat well. I would definitely recommend purchasing these budget-friendly, high performance outboards. These are totally worth the money! If you any further query or discussion, please leave a comment below in the comment box.

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