Mercruiser is one of the outboard motors that has recorded good patronage.
Mercruiser outboard motors come in two stroke and four stroke variant.
These outboard motors help your boat to move well on the water.
But Mercruiser Vibration problems can occur while using the boat.
Some of the reasons why Mercruiser outboard motors vibrate include overloading, lack of timely maintenance, use of bad fuel, bad ignition system, use of bad fuel to oil ratio for the 2 stroke variant and other issues like low engine compression.
These problems reduce the performance of the Mercruiser outboard motor.
When this occurs, the boat ride will be poor due to the vibrations from the outboard motor.
In this guide, you will learn how you can easily fix a vibration problem when it occurs in your Mercruiser outboard motor.
Why Mercruiser Outboard Motor Vibrates And How To Fix It
1)Faulty Ignition System
The ignition system is one of the most important parts of an outboard motor.
The ignition system helps in the generation of spark in the outboard motor.
This includes parts like the stator, ignition coil and the spark plug.
The efficiency of the outboard motor is reduced when any of the ignition system component is faulty.
When an ignition system is faulty, the fuel in the combustion chamber will not be efficiently ignited.
This will lead to hard starting and vibrations if the outboard motor is already running.
Solution
a)Fix Faulty Ignition Component
The components that make up an outboard ignition system are very many.
This includes components like the spark plug, stator, ignition coil and even the battery.
These components help deliver charge to the combustion chamber to ignite the fuel mixture.
With this, power is generated in the outboard motor.
2) Use Of Contaminated Fuel
For an outboard motor to function, the availability of fuel is very important.
This is because fuel is what helps in generating power in a Mercruiser outboard motor.
The way this happens is that fuel is ignited in the combustion chamber.
As the fuel gets ignited, pressure will be built up in the combustion chamber.
This pressure moves the piston down to create a circular motion that helps power components like the propeller.
But for energy release to be efficient, the fuel that is ignited in the combustion chamber has to be good.
If the fuel is contaminated, the magnitude of power released from the combustion chamber will be small.
A contaminated fuel contains water and debris which will end up clogging the fuel filter or preventing efficient ignition when the fuel contains water.
Solution
a)Use Good Fuel
If you want to have a good performance when making use of your outboard motor, you need to use good fuel.
This fuel has to be free from contaminants like water and particles.
With this, the performance of the outboard motor will be great.
This will help avoid vibration problems in the Mercruiser outboard motor.
3) Clogged Fuel Filter
As fuel leaves the storage tank to the combustion chamber, it has to be free from contaminants.
The manufacturers of outboard motors have developed measures to help make this possible.
This is by the use of a fuel filter.
The fuel filter helps in filtrating fuel and stopping the dissolved contaminants in it from getting to the combustion chamber.
But as time goes on, these contaminants increase in the fuel filter.
Due to this, the excess contaminant ends up blocking the free flow of fuel.
This limits the volume of fuel that is being sent to the combustion chamber of the outboard motor.
When the volume of fuel sent to the combustion chamber is limited, the combustion chamber will be starved of fuel which will cause performance lag.
One of the ways in which this will show up is that the Mercruiser outboard motor will vibrate when being used due to low power output from the engine.
Solution
a)Unclog Fuel Filter
The role of the fuel filter in helping the outboard motor achieve good performance is very high.
If the fuel filter is good, the outboard motor will perform well.
But if the fuel filter is bad, the outboard motor performance will be bad.
When you discover that the fuel filter in your Mercruiser outboard motor is bad, you have to change it to a good one.
4) Faulty Fuel Pump
For an outboard motor to function well, the combustion chamber has a role to play.
This is because for power to be generated from the outboard motor, fuel has to be ignited.
It is in the combustion chamber that this ignition of fuel occurs.
But for efficient power to be produced, the combustion chamber has to burn more fuel.
In the supply of fuel for combustion to the combustion chamber, the fuel pump makes this possible.
The fuel pump helps in sending fuel at the right pressure and volume to the combustion chamber.
If the fuel pump is faulty, the performance of the Mercruiser outboard motor will be bad.
This is due to low volume of fuel supplied to the combustion chamber by the fuel pump.
Solution
a)Replace Bad Fuel Pump
When your outboard motor is not producing much power, you have to troubleshoot for the cause.
One of the components of the outboard motor that you have to troubleshoot is the fuel pump.
In doing this, you have to seperate the output valve of the fuel pump and observe the volume of fuel the fuel pump outputs.
If it outputs very low volume, then the fuel pump is bad and has to be changed.
This will help in supplying the correct volume of fuel needed in the combustion chamber.
With this, the performance of the Mercruiser outboard motor will improve.
This will help solve mercruiser vibration problem if it was due to fuel starvation caused by a bad fuel pump.
5) Bad Fuel To Oil Mix Ratio
The ratio of oil used in Mercruiser 2 stroke outboard motor is very important.
This will affect the performance of the outboard motor.
If the oil in the fuel mixture is too much, the engine will not perform well.
This is because the fuel mixture will be too rich in oil.
Due to this, the spark plug will not be able to efficiently ignite the fuel mixture in the combustion chamber.
This will cause incomplete combustion and will lead to smoking of the Mercruiser 2 stroke outboard motor which will cause fouling of spark plug too.
If the oil in the fuel mixture is too small, the engine of the outboard motor might be destroyed due to less lubrication.
That is why you have to make sure that you use the right fuel to oil mix ratio when running your Mercruiser 2 stroke outboard motor.
Solution
a)Use Correct Fuel To Oil Mix Ratio
To achieve good performance from your 2 stroke Mercruiser outboard motor, you have to use a good mix ratio.
This is usually a 50:1 mix ratio.
This will help your outboard motor to function well.
6) Bad Ignition System
For the Mercruiser outboard to produce power, combustion of fuel has to take place in the combustion chamber.
But for the combustion to take place, the fuel mixture has to be ignited.
This is usually done by the ignition system.
The ignition system produces a spark that helps ignite fuel mixture in the combustion chamber.
The spark plug is the final channel where super charged electric charge from the ignition coil is used to ignite fuel mixture in the combustion chamber.
But if any of the ignition system component is bad, power loss will occur in the Mercruiser outboard motor.
Solution
a)Fix Faulty Ignition System
If you experience Mercruiser vibration issues, it is usually a low power generation problem from the engine most of the time.
This can occur if the ignition system is not functioning well.
This can be a spark plug or ignition coil that is faulty.
When you discover any of the faulty ignition system, you have to fix it.
This will help your Mercruiser outboard motor to perform well with minimal to no vibrations.
7) Overloading Causes Mercruiser Vibration Problems
When using your outboard motor, you have to make sure that you do not overload the boat the outboard motor is attached to.
If the load is higher than the capacity of the outboard motor, your outboard motor will vibrate especially when it is accelerating.
That is always due to the fact that the outboard motor cannot comfortably produce the power needed to move the overloaded boat
Solution
a)Do Not Overload Mercruiser Outboard Motor
Overloading will reduce the efficiency of your outboard motor.
It will lead to power lag and vibrations.
To overcome this, you have to make sure that you do not overload the boat that the Mercruiser outboard motor is attached to.
This will help the outboard motor to give a flawless performance.
8) Loose Contact With Boat
The outboard motor is always vibrating when it is functioning.
This is due to the movement of pistons in the combustion chamber.
But this vibration can be easily minimised if the Mercruiser outboard motor is well attached to the boat.
If it is not well attached to the boat, then the vibrations will be high
Solution
a)Attach Mercruiser Outboard Motor Securely To Boat
If your outboard motor is not well secured to the boat, there will be vibrations.
To solve this, you have to make sure that the outboard motor is well secured to the boat.
This will help prevent Mercruiser outboard motor from vibrating when it is working.
9) Low Compression In Cylinder
Low compression in the cylinder is one of the reasons why boat vibration at low speed occurs.
For an outboard motor to function, power has to be produced in the combustion chamber.
This helps the propeller to rotate and move the boat.
But for this power to be created in the combustion chamber, the cylinder has to maintain a good compression.
This is what helps maintain enough pressure produced through combustion to push the piston.
With the movement of the piston, the propeller can function.
But if the engine components have issues, this will lead to poor compression in the cylinder.
This will reduce the power produced from the outboard motor during combustion of fuel mixture.
This will cause Mercruiser vibration problems when making use of your boat.
To avoid this, you have to make sure that your Mercruiser outboard motor maintains a good compression.
This can be done by testing the compression of the Mercruiser outboard motor.