When mercury 9.9 4 stroke won’t stay running, there are a lot of reasons that can cause this.
Irrespective of the reason, one thing is always common as an outcome.
The outcome is that the use of that outboard motor will be unreliable.
Some of the reasons why mercury 9.9 4 stroke stalls include exhausted fuel, stuck carburetor float, bad spark plug, bad fuel, low oil level, overheating and overloading.
When the outboard motor faces any of these situations, then it will stall when in use.
Why Mercury 9.9 4 Stroke Will Not Stay Running Or Stalls
1) No Fuel In Tank
When it comes to keeping your outboard motor running, fuel is a very important component.
Without it, there will be no combustion in the combustion chamber.
That is why it is one of the components to give a check on when your outboard will not stay running.
Before you embark on any journey with your outboard motor, you have to know how long it will last.
This will help determine if you are to carry a backup fuel in case your fuel is exhausted along the journey.
Driving across a long distance with an outboard motor with a small fuel tank will cause stalling along the way when the fuel is exhausted.
Solution
a) Refill Tank With Fuel
An exhausted fuel tank is one of the causes of stalling when you use your outboard motor.
If you check and you discover that it is the cause, you have to fix the issue.
This can be done by refilling the fuel tank with fuel.
This will help put your outboard motor in active use again.
2) Stuck Carburetor Float
The carburetor float is a very important component of an outboard motor.
It is very important that it controls the performance of an outboard motor.
it it works well, then you will have an outboard motor that will output a great performance.
But if it develops a fault, then the performance of the outboard motor will suffer.
One of the ways in which the carburetor float develops a fault is when it’s float gets stuck.
When this happens, the carburetor will begin to behave abnormally.
If the float is stuck in an open position, then excess fuel will be released by the carburetor.
This will cause leakage of the carburetor with other issues like smoking and engine flooding.
If the carburetor float is stuck in a closed position, then there will be no fuel released into the carburetor.
This will cause the combustion chamber to be starved of fuel.
This is one of the reasons why mercury 9.9 4 stroke stalls when it is in use.
Solution
a) Free Stuck Carburetor Float
If you discover that the reason why your outboard motor wont stay running is due to a stuck float, you have to fix it.
This can be done in two ways.
The first way is to rebuild the carburetor.
This will help free the stuck float.
The second way is to buy a new carburetor for replacement.
This should be done if the stuck carburetor is really damaged.
With this, your outboard motor will enjoy a flawless performance.
3) Bad Spark Plug
In the functionality of a 4 stroke outboard motor, the spark plug plays a vital role.
Without the spark plug,, the outboard motor will not even start.
This is because for an outboard motor to start, power has to be produced.
This is made possible through combustion in the combustion chamber.
But for the combustion to take place, there have to be a spark.
This spark production is done by the spark plug.
Without a good spark plug, there will be no spark to release power through combustion.
This is one of the reasons why mercury 9.9 four stroke won’t stay running.
Solution
a) Replace Bad Spark Plug
When you discover that your spark plug is bad, you have to make sure that you replace it.
In doing so, you have to make sure that you replace it with a good one.
This will help your outboard motor to continue running when you are using it instead of stalling.
4) Bad Fuel
Having a bad fuel in the combustion chamber is very bad.
This will lead to a lot of issues when you are making use of your outboard motor.
One of the ways in which this issue shows up is stalling.
With a bad fuel in your outboard motor, there will be no efficient combustion of fuel.
This will lead to stalling in which the outboard motor cannot stay running especially when you are accelerating.
That is why you have to make sure that the fuel that you use in an outboard motor is a good one.
Solution
a) Use a Good Fuel
When you use a bad fuel to power your outboard motor, you will experience a performance lag.
To correct this, you have to make sure that you drain the bad fuel from your outboard motor.
After that is done, fill the gas tank with a good fuel.
With a good fuel, you will experience a much better performance when you are using your outboard motor.
5) Low Oil Level
For an outboard motor to perform well, the presence of oil is very necessary.
This helps in so many things like lubrication.
Oil also helps in reducing the temperature inside the engine.
That is why it has to be kept at an optimum level when making use of an outboard motor.
If the quantity that is present in the outboard motor is too low, there will be issues.
But in this modern age, outboards are designed to stop some damages from occurring.
That is why there are a lot of sensors that help to achieve this.
In an outboard motor, there is a sensor that helps in preventing damage due to oil shortage.
When there is an oil shortage in an outboard motor, the sensor will activate a stalling of the outboard motor to prevent damage from occurring due to a low oil level in the outboard motor.
Solution
a) maintain Optimum Oil Level
When you want to avoid a situation in which mercury 9.9 4 stroke will not stay running due to low oil level, you have to make sure that the oil level is not low.
This can be done with the use of an oil dip stick.
If you discover that the oil level was not ok when you changed the oil, you have to top it to the correct level.
This will help avoid stalling when you are using your outboard motor.
6) Overloading
Another reason why mercury 9.9 four stroke won’t stay running is due to overload.
Every outboard motor and boat has a limit to the load they can carry or support.
In a boat, this is found on the capacity plate.
Every outboard manufacturer has a set limit of load that the outboard can comfortable transport.
If you impose an extra load on the outboard motor, then there will be consequences.
One of the ways in which this will show up is that the outboard motor will start misbehaving.
This can be in the form of vibrating when accelerating or stalling.
Solution
a) Do Not Overload Outboard Boat
To make sure that you avoid the shutdown of your outboard motor due to an overload, you have to watch out for the load you put in yout outboard motor.
In doing this, you have to make sure that you do not overload your boat.
With this, your outboard motor will be able to function well.
7) Overheating
Overheating is a very serious issue when it comes to the use of an outboard motor.
To avoid an extensive damage, a disconnect is created to shut down the outboard motor when it overheats.
This is one of the reasons why mercury 9.9 4 stroke stalls when being used.
This is usually caused by a faulty outboard cooling system.
Solution
a) Fix Bad Cooling System
If you discover that your outboard motor shutsdown due to overheating, you have to fix it.
Majority of overheating in an outboard motor is usually caused by a bad cooling system.
This can be from a bad impeller or clogged cooling pipe.
When you discover the fault, you have to make sure that you fix it.
This is one of the things to do when mercury 9.9 4 stroke won’t stay running due to overheating.
This will help prevent overheating from occuring when you use your mercury outboard motor.