Why a Boat Vibrates When Accelerating And How To Fix It

Most of the times when a boat vibrates when accelerating can cause a serious panic when driving your boat.

This could be as a result of minor or major faults in the mechanical parts of the boat.

Vibrations in a boat when accelerating is due to damaged or loose propeller, inadequate fuel supply to outboard motor, loose engine mount or clogged fuel filter.

When this occurs, you should make sure that you correct it when you reach the boat yard before having another boat ride.

Failure to make the correction to the faulty part can be very dangerous.

In this guide, you will learn why boat vibrates when accelerating and how to fix it.

What Causes a Boat To Vibrate When Accelerating

Boat vibrations when speed increases do not just happen, there is always a boat faulty part that causes it.

Some of the causes includes;

1) Bent Shaft

Having a bent shaft in your boat can be very dangerous.

It will lead to the development of vibrations when you are accelerating your boat.

This is because the shaft is not well aligned.

When this occurs, you will start to experience some level of vibration when you drive your boat.

It gets worse as the acceleration of the boat gets higher.

 So when you discover that your boat shaft is bent, you have to make sure you align it well or change it so as to have a smooth ride with your boat.

2) Damaged Bearings

The bearing helps in providing hitch free rotation.

This is assisted by the balls in the bearing.

The problem comes in when the bearing becomes faulty due to broken balls inside the bearing.

This will lead to an unbalanced circular movement.

As a result of this, this will transfer to the performance of the boat.

This causes the boat to vibrate when accelerating the boat.

Apart from the unbalanced circular movement a bad bearing causes, it is very bad to keep using it.

This is because the broken bearings can move into delicate parts and cause more damage to your boat mechanical parts.

3) Bad Oil

Have you ever compared the performance of your boat when you use a new oil to when the oil is stale?

If you have ever done such a comparison, you will discover that when the oil is new, the performance of the boat will be great.

Even when you are accelerating, the performance will still be great.

But this is not really possible when the oil in the boat engine is stale.

A bad or stale boat engine oil reduces the performance of a boat engine.

This causes issues like vibration of the boat due to poor engine performance.

This is even worse when you are accelerating your boat to a higher speed level.

At such situation, boat vibrates when accelerating due to a stale oil in the engine of the boat.

4) Loose Engine Mount

Having a routine check on your boat is very important.

At such checks, one of the things that is supposed to be given a thorough check is the engine positioning.

Make sure that you check if the engine is tightly secured on the engine mount.

If it is not, this will cause a problem to the optimal functionality of your boat.

A loosely mounted engine will always cause a lot of vibrations on the boat.

This is because when the boat engine is running, a lot of movement takes place inside the engine.

This leads to a lot of vibrations.

But this vibration is controlled by the engine mount.

If the engine mount of the boat has a loose contact with the boat engine, this will cause a lot of erratic movement.

This will lead the boat to vibrate.

The vibration of the boat gets worse as the acceleration increases.  

5) Bad Fuel Pump

Having a bad fuel pump on your boat can be very bad.

That is why it is very important to always check the symptoms of a bad fuel pump on a boat so as to correct it early.

When the fuel pump of a boat is bad, it will not supply the boat engine the optimum amount of fuel the engine needs to run smoothly.

This will result in jerking which makes the boat to vibrate.

It is even worse when you try to accelerate the boat.

In such a case, the boat vibrates when accelerating if the fuel pump is bad.

This is because the fuel that is supplied to the boat engine is not sufficient enough for the engine to burn and produce power to meet the applied load.  

At such a point, this will cause the boat to vibrate.

6) Faulty Spark Plug

Spark plugs are very important in an engine as far as starting an engine is concerned.

If the spark plug is bad, then starting an engine will be very hard or impossible.

A bad spark plug also affects the performance of a boat when it is running.

This will not make the boat to move well on water when the plug is bad.

Due to this, all cylinders will not be able to run well.

This will translate to vibrations to the boat.

This gets worse when you are accelerating the boat.

When a boat is accelerated, it requires more power from the engine to make the boat move fast.

This power is also enhanced by a good spark plug.

If the spark plug is faulty, more cylinders in the boat engine will not perform well.

Due to this, the engine will be jerking as it cannot produce the needed power to move the boat faster.

This will make the boat to vibrate as well.

This is one of the problems a suzuki 115 four stroke outboard motor encounters.

7) Clogged Fuel Filter

To help the engine of a boat last longer, it must be free from debris.

This is done with the use of a fuel filter.

This helps in stopping debris from entering the engine of a boat when it is running.

But when the debris retained is too much, the fuel filter gets partially or fully blocked.

This limits the amount of fuel that enters the engine in a negative way.

Due to this, the engine of the boat will be struggling to effectively run the boat.

As a result of this, the engine will be jerking which causes vibration.

When you accelerate your boat, the demand for power from the engine increases.

This causes the fuel consumption to increase too.

But due to the clogged fuel filter which limits the amount of fuel the engine gets, the engine jerks.

This makes boat vibrate when accelerating.

At worse cases, the boat engine will completely stop working due to low supply of fuel to the engine.

8) Damaged Or Loose Propeller

Having a bad propeller on your boat can lead to very poor boat performance.

Apart from the engine of the boat, the propeller of a boat plays a vital role in the optimal functionality of a boat.

That is why it should be taken care of with great priority.

This can be done by performing routine checks on your boat propeller.

Make sure to remove debris that are attached to the propeller of your boat.

This could be things like sea weed or a nylon that is wrapped around the propeller.

This will cause the propeller to perform poorly if they are not removed.

Also this will cause situations like vibration of boat when accelerating.

How To Stop Boat Vibration When Accelerating

1)  Align or Replace a Bent Shaft

When the shaft on your boat is bent, it will lead to vibrations.

To fix this, make sure that you align the shaft well.

If the condition of the shaft is too bad, you should consider replacing the shaft.

2) Use a Good Propeller

If the propeller that you use on your boat has any fault, you should consider replacing it.

When replacing the propeller with a new one, make sure that it is the right fit for your boat.

3) Use Good Spark Plugs

One of the major reasons why boat vibrates when accelerating is when the spark plugs are bad.

This will cause all cylinders not to work well.

Due to this, the power output of the boat engine will be low.

As a result, the engine will jerk and thereby transfer vibrations to the boat.

To avoid this, make sure that you use good spark plugs in your boat engine.

4) Position Engine Tightly On Engine Mount

One of the things you should check when your boat vibrates badly is the firmness of your boat engine to the engine mount.

If the boat engine is not well mounted, the engine will always move erratically due to rapid movement of cylinders in boat engine.

To solve this issue, make sure that you hold the boat engine tightly to the  engine mount.

5) Use a Good Fuel Pump

Lack of adequate fuel supply to the boat engine is really bad.

It gets worse when you are increasing the speed of your boat.

An increase in speed demands more power which translates to more fuel intake by the engine.

If the bad fuel pump does not supply the optimum amount of fuel in such a condition, the boat jerks.

To  solve this, make sure that you test the  fuel pump to make sure it is performing optimally.

If the fuel pump is bad, consider replacing it with a good one.


Having a boat ride is always a pleasant way to enjoy recreational times.

But a bad mechanical component can ruin the fun easily.

This is when boat vibrates when accelerating.

But it can be easily solved as explained in this guide.

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