The mercury outboard motor is a favorite to a lot of people when it comes to choosing an outboard motor.
This is one of the reasons why people love the 4 stroke 30 HP models.
Some mercury 4 stroke 30 hp problems include outboard not starting, overheating, high fuel consumption, propeller problem and outboard vibration when accelerating.
In a lot of cases, it is always a minor issue if you maintain your outboard well.
This guide will familiarize you with some of the mercury fourstroke 30 hp issues you may likely encounter and how to solve them.
Mercury 4 Stroke 30hp Problems And Its Causes
1) Engine Not Starting
Having an engine that will not start is one of the problems automobile owners face at some point.
This is also faced by the mercury outboard owners too some times.
This occurs when you try to start your mercury outboard motor and it refuses to start.
There are a lot of reasons that lead to this.
a) No Fuel In Gas Tank
For the mercury outboard motor to run well, it needs to have a good engine.
But for a good engine to function well, there are a lot of components that help in achieving that.
One of these is the fuel in the fuel tank.
When there is sufficient fuel in the fuel tank, your outboard motor will start well.
But if there is no fuel in the tank, then your mercury 30 HP will not start.
So when you are faced with this type of problem in which your outboard motor is not starting, you have to check the fuel tank.
If there is no fuel in the tank, you have to put fuel into the fuel tank and try to start again.
b) Bad Spark Plug
For a mercury outboard motor to start, the engine has to function.
But for the engine to function, it has to burn fuel.
This combustion in the cylinder is made possible with the help of the spark plug.
The spark plug helps in delivering the supercharged volts which are in thousands of volts to the engine.
With this high voltage, the fuel in the combustion chamber is easily burned.
This helps the outboard motor to start and also produce power for its functionality.
But if the spark plug is bad, then the outboard motor will not be able to start.
c) Flooded Engine
Fuel is needed in the combustion chamber for combustion to take place.
But the volume of fuel needed must be optimal.
If the volume of fuel released into the combustion chamber is too much, this will lead to engine flooding.
This will cause the outboard motor not to start.
d) Less Charge Supply To Spark Plug
For the spark plug to function well, it has to be able to deliver charge to the engine for combustion.
But the thing is that this electric charge is not produced by the spark plug.
This is done with the help of components like the CDI box, stator and ignition coil.
If any of these parts are damaged, then the spark plug will receive a lesser voltage.
This will inhibit the outboard motor from starting.
a) Replace Faulty Stator Or Ignition Coil
When you discover that the ignition coil in the mercury outboard motor is bad, you have to make sure that you replace it.
In doing so, make sure that you replace it with a good one.
This will help deliver the needed amount of charge to the spark plug for an effective burn in the combustion chamber.
b) Add Fuel To Fuel Tank
As you keep using your outboard motor, some parts will gradually deteriorate.
This includes the spark plug.
When the spark plug is bad, it will not be able to deliver the optimum amount of charge needed for combustion.
As a result of this, the outboard motor will not start.
To solve this, you have to make sure that you replace a faulty outboard motor with a good one.
2) Outboard Motor Vibrating When In Use
Another mercury 4 stroke 30 HP problem you may encounter is vibration while in use.
This can be when you are not accelerating.
Vibration of outboard motor can also occur when you are accelerating.
it is always a very unpleasant occurrence when it occur.
This is due to the imbalance that the vibrations cause.
a) Bad Spark Plug
For the outboard motor to produce power, the engine has to produce the power.
This is done with the help of the spark plug.
If the spark plug is good, then the cylinders in the engine will all functuion well to produce the needed power.
But if the spark plug is bad, then the cylinders with the bad spark plug will not function.
This will reduce the power output from the outboard motor.
Due to this, issues like vibrations will occur especially when accelerating outboard motor due to loss of power.
b) Bad Fuel Supply
When there is less fuel supply to the combustion chamber, the engine will not have an optimal burn.
This will lead to less power output from the outboard motor which will show up in vibrations.
This gets worse when accelerating the outboard.
At worse cases, the outboard motor will shutdown while accelerating if the fuel supply components are bad.
This could be a faulty carburetor or bad fuel pump.
c) Loose Engine Positioning
When the outboard motor is functioning, it produces vibrations due to the movement of the pistons.
But this is easily controlled when the outboard motor is properly mounted.
If not properly mounted, then the outboard motor will be shifting erratically thereby causing vibrations when in use.
a) Use Good Spark Plugs
When your outboard motor is vibrating when in use, it can be caused by a bad spark plug.
A bad spark plug makes the cylinder not to function well.
This will lead to power loss and makes the boat vibrate when power is needed.
To solve this, you have to make sure that you change a bad spark plug to a good one.
b) Use a Good Fuel Quality
A bad fuel quality can also affect the performance of your outboard motor.
If the quality of the fuel used in the outboard motor is not good, then the combustion in the cylinder will be affected.
This will result in a poorly functioning outboard motor.
This will show up in vibrations when in use.
To solve this, you have to make sure that you use a good quality of fuel.
3) Mercury 30 Hp Overheating
An overheating problem is one of the problems a lot of outboard motor owners face.
It is also one of mercury 4 stroke 30 HP problems that exist.
This is always a rare problem when you perform timely maintenance on your outboard motor.
An overheating occurs in the outboard motor when the internal temperature of the outboard motor is too high.
This is always very dangerous and can destroy the outboard motor.
a) Bad Impeller
Majority of outboard motors rely on water cooling system to help regulate the temperature of the outboard motor.
For this to be possible, the impeller has to pump water to help cool the outboard motor.
If the impeller is bad, then this will not be possible.
Due to this, the temperature will keep building up which leads to overheating.
So when you discover that your outboard motor is overheating, check the cooling system.
a) Replace a Bad Impeller
Overheating in an outboard is usually due to the poor functionality of the cooling system.
It could be that the valves are clogged with dirt or that the impeller is bad.
When this occurs, the impeller that is faulty will not be able to pump water to cool the outboard motor.
To solve this, you have to make sure that you change the impeller to a good one.
This will help in solving the overheating problem.
4) Carbon Build Up
As the outboard motor functions, it gives out bye products after combustion.
This is usually carbon and other gases.
This is done through the exhaust system.
But this carbon is not 100% released.
Some will clog and build up over time which will reduce engine efficiency.
a) Continuous Engine Use
As you keep using your outboard motor, carbon will always get released from the engine after combustion.
Some will not leave and will gradually keep building up as you keep using your outboard motor.
b) Poor Outboard Maintenance
After a certain usage interval, it is always advisable to run maintenance on some parts of the outboard motor.
This cuts across lubrication of moving parts and change of oil too.
Decarbonizing the outboard motor is also done when running maintenance on your outboard motor.
This helps the outboard motor to perform flawlessly when in use.
But if you are carefree with your outboard motor maintenance, then carbon build up is one of the problems you will likely face.
a) Perform a Maintenance
When you discover that there is a carbon build up in your outboard motor, you have to make sure that you contact a technician to perform servicing.
This will help remove the excess carbon build up.
With this, your outboard motor will be able to function well.
5) Engine Shutting Down On High Acceleration
The more you accelerate your outboard motor, the more it requires power from the engine.
If the engine is not effective enough, then the engine will shut down.
a) Bad Carburetor or Fuel Pump
When an outboard motor accelerates, it will require more power.
This will also lead to a higher fuel burn in the combustion chamber.
But if the carburetor or the fuel pump is bad, then it will not be able to supply the needed volume of fuel to the engine.
This will cause the outboard motor to shutdown when accelerating.
b) Bad Spark Plug
Spark plugs help the engine to burn fuel and produce power.
If they are bad, then the performance of the engine will be poor.
This is seen when a mercury four stroke 30 HP shuts down when accelerating due to less power from the engine with bad spark plug.
a) Replace a Bad Carburetor With a Good One
When you have your mercury 4 stroke 30 hp outboard motor shutting down when accelerating, you have to troubleshoot.
This will help show the cause of the problem.
If it is caused by a faulty carburetor or fuel pump that limits fuel output to the combustion chamber, you have to replace it.
In replacing it, make sure you use a good one.
b) Use Good Spark Plugs
When you discover that your mercury 4 stroke outboard motor is not functioning well due to a bad spark plug, you have to change it.
When changing, make sure that you change it to a good one.
6) Engine Shuts Down After Starting
In some cases, the outboard motor might start but does not stay running.
The common cause of this a lot of times is usually poor fuel quality or a bad spark plug.
This is another mercury 4 stroke 30 HP issue that is experienced some time.
a) Bad Fuel Quality
When you are using your outboard motor, you have to pay attention to the quality of fuel used.
If the quality of fuel used is good, then your outboard motor will function well.
But if the quality of the fuel that is used is bad, then the performance of the outboard motor will suffer.
This is seen when the fuel contains contaminants like disolved solutes and water.
When this occurs, then the outboard motor will shut down after starting.
b) Bad Spark Plug
A bad spark plug in an outboard motor leads to a lot of problems.
One of the problem it causes is causing an outboard motor to shut down after starting.
c) Bad Carburetor Or Fuel Pump
For the engine to function well, it requires fuel.
But this requirement of fuel is dynamic.
This means that the volume of fuel required changes depending on what the outboard motor does.
When it is just starting, it will require less fuel.
But to keep running, it will require continuous supply of fuel.
If the carburetor or the fuel pump is faulty, then this will not be possible.
a) Use Good Fuel Quality
When you are making use of fuel in your outboard motor, make sure it is a good one.
It should be free from particles and water.
b) Use a Good Spark Plug
To help your outboard motor achieve a flawless performance, make sure that you use a good spark plug.
If you discover that the spark plug is bad, make sure you change it to a good one.
c) Replace a Bad Carburetor With a Good One
Always use a good carburetor in your outboard motor.
A bad one will end up starving the engine of fuel for an effective burn and performance.
To avoid this, make sure that you use a carburetor that is good so as to supply the optimum volume of fuel to the combustion chamber.
7) Clogged Carburetor
Sometimes impurities will enter your carburetor and cause issues with the carburetor.
This is seen when the carburetor is clogged with debris or impurities.
a) Bad Fuel Quality
When a carburetor is clogged, one of the major cause of this has to do with the quality of the fuel used in the outboard motor.
If the fuel quality is good and free from impurities, then the carburetor will not be clogged.
But if the quality of fuel is poor with dissolved particles in it, the carburetor will be affected.
This will lead to the deposition of the impurities in the carburetor which will end up clogging the carburetor.
a) Use Good Quality Fuel
When making use of your outboard motor, make sure that you use a good quality fuel.
The fuel should be free from water, solids and dissolved contaminants.
This will help the outboard motor to function well as well as improve the lifespan of the outboard motor components like the carburetor.
8) Propeller Problems
The mercury 4 stroke 30 horse power is built with durability in mind.
Irrespective of this, you will face propeller problems in one way or the other.
In most of the times when this occurs, it is usually due to an improper usage of your outboard motor.
But when the propeller is bad, then the performance of the outboard motor will be affected.
a) Use In Shallow Water
If you want your outboard motor to last longer, you have to be careful of the water you use it on.
If you use it on a water body that is too shallow, then it will surely have issues.
One of the parts that will be easily affected is the propeller of the outboard motor.
This is because the propeller is the lowest part of the outboard motor.
When you use your outboard motor on a water surface that is too shallow, then the propeller will easily hit the water bed or rocks.
This will cause a damage in the alignment of the propeller and reduce its efficiency.
Apart from hitting rocks, it can come in contact with sea weed which can trap the propeller from functioning well.
b) Poor Storage
When you store your outboard motor wrongly, you will damage some parts.
a) Do Not Use Outboard Motor On Extremely Shallow Water
When you see that a water body is very shallow, do not use your outboard motor on it.
This will help prevent the chances of a sea weed or rock from destroying the propeller
b) Store Outboard Motor Well
When you are done with using your outboard motor on the water surface, you have to store it.
In storing it, you have to make sure that you store it well.
This will help prevent damage of the propeller or any other part of the outboard motor.
One of these parts is the propeller of the outboard motor.
9) Mercury 30 Hp Propeller Pushing Out Too Much Water
When the outboard motor is functioning, the propeller is always in a circular motion.
This will lead to pushing of water to create a force that moves the boat.
Due to this, water will be pushed above the surface of the water.
But too much of water pushed above the water surface is a sign that the outboard motor is not properly mounted at the right height.
a) Outboard Motor Is Mounted Too High
When you discover that your mercury 30 hp is pushing too much water above the surface of water, you have to check the height of alignment.
This is because when the outboard motor is mounted too high, water will really be pushed above the water surface.
This also leads to propeller efficiency loss and causes the boat not to move fast.
a) Align The outboard Motor Well
When you observe that the outboard motor is not performing well due to wrong positioning, make sure that you position it well.
This will help your outboard motor propeller to function effectively.
10) Mercury 4 Stroke 30 HP High Fuel Consumption
When making use of your 30 hp mercury outboard motor, you should not expect the same fuel usage with a 1 hp outboard motor.
But at some point, you will realize that your 30 hp mercury outboard motor is consuming more fuel than it used to.
When this occurs, it is usually a problem which increases cost of usage as you will need to spend more on fuel.
This is bad especially when you are using the outboard motor for commercial use.
a) Oil Problem
When you start having oil issues with your mercury outboard motor, you will have extended problems too.
One of these problems will be that you will have a higher fuel consumption rate.
That is why you have to make sure that you perform an oil change in time.
When doing this, make sure that you are making use of a good quality oil.
If you use a poor quality oil, it will not help the outboard motor to perform well and will also lead to increase in fuel consumption.
a) Use a Good Quality Oil And Change On Time
When it comes to the lifespan and performance of your 4 stroke outboard motor, the oil plays a vital role.
When it is due for a change, make sure that you change it.
When changing, make sure that you use the right type.