6 Symptoms to Detect a Faulty Fuel Pump on Mercury Outboard

If you are having disruptions with your Mercury outboard fuel pump, you may be frustrated. You need to know about the problem. However, you can not address this without proper symptoms. So, what are the bad Mercury outboard fuel pump symptoms?

Sputtering while igniting the engine is the most common symptom for it. Excess consumption of fuel, an overheated outboard motor, and faulty valves are symptoms too. You may also hear significantly less sound while igniting the motor too.

These are the main symptoms you may come across. To know more in detail, you need to read along. We have got many useful insights here. So, get into it right away.

How to Know if a New Fuel Pump is Required?

Addressing the right symptom is very important for any type of problem. A Mercury outboard fuel pump leaves a number of common symptoms that you can look at. So, here we have covered the obvious symptoms.

Symptom 1: Sputtering 

If you see your boat engine sputtering or struggle quite a lot to start, your fuel pump is faulty. This is one of the most common symptoms you may come across.

You may see your boat shaking quite noticeably when you try to start your boat engine in this case.

Symptom 2: Excessive Fuel Consumption

You definitely know the usual consumption of gas for your boat is efficient. However, if you notice your Mercury boat to be consuming excessively, hold on.

You have to understand that this is because of a faulty Mercury outboard fuel. To be precise, the consumption can go beyond 2 to 3 times more than the usual one.

Symptom 3: Overheated Outboard Motor

In general, overheated outboard motors are cooled down with water consistently. But if you see your outboard motor to be overheated, that one would be a symptom for a bad fuel pump.

If you smell like a metal body starting to burn, you have to understand that the outboard motor is overheated.

Symptom 4: Less Sound While Igniting the Motor

We all know the usual sound of the Mercury outboard motor when we ignite this. However, there would be comparatively lower sound with this if the fuel pump is faulty.

The sound of the motor would be as low as soothing music in case you want an example.

Symptom 5: Faulty Valves

The valves in your boat would help in flowing the gasoline to the motor effectively. So, in case of a faulty valve, your motor would not receive a sufficient amount of gasoline. 

Due to this, the boat would often stop in the middle of the journey. So, this comes as a symptom of a faulty fuel pump.

Symptom 6: Diaphragmatic Leakage

Diaphragm leakage is another symptom of this. To reckon this, you would often be smelling gas, especially when you increase the RPM.

So, these are the symptoms that you may experience from a faulty fuel pump.

Causes of a Fuel Pump Failure on a Mercury Outboard Engine

There are some obvious reasons that lead to a Mercury outboard’s bad fuel pump. So, here we have covered the main causes of it. Take a look.

  1. Bad fuel pumps are mainly caused by electrical disruptions and faults.
  2. Due to a build-up of dust and dirt particles with time, the fuel pump goes bad.
  3. Insufficient filtration can lead to this problem.
  4. Due to fuel starvation, there is an insufficient flow of fuel which leads to a faulty fuel pump.

These are the main causes of a bad fuel pump.

Cost to Replace and Repair Mercury Outboard Faulty Fuel Pump

This segment would give you an idea about the cost of replacing and repairing the Mercury fuel pump. Take a look.

Mercury Outboard Fuel PumpCost of RepairCost of Replacement
MinimumAround $580Around $850
MaximumAround $800Around $1200

Tips on Preventing the Mercury Outboard Fuel Pump Problem

Finally, we have got here some useful tips for you so that you can prevent your Mercury outboard fuel pump from further problems. Take a look.

  • You must always keep your fuel tank full. Try to maintain regularity with refueling the tank.
  • When you are looking for a gas station to refuel the tank, consider the newer ones.
  • If you are ever replacing the current one, go for the high-quality ones rather than going for the reasonable ones.
  • Keep the outboard motor and the surroundings clean all the time. Try to clean these areas at least once every 3 days.

So, these are the tips that you can count on to maintain your Mercury outboard fuel pump well.


With all the info above, you must not have any more confusion regarding the concern. Finally, here we have got some additional info that may help you to complement the concern. Take a look.

Can you hit a Mercury outboard fuel pump to make it work?

Yes, hitting a Mercury outboard fuel pump can be effective to make it work again. However, it is not always possible. Note that you must not hit it so hard as this is just a simple blow to see if it coincidentally starts working again.

Can a Mercury outboard fuel pump be weak but still work?

Yes, a Mercury outboard fuel pump may be weak but still, keep on working. However, it would not work perfectly and your boat would have severe issues and difficulties to get started.

Can a faulty fuel pump overheat the Mercury outboard engine?

Yes, a faulty fuel pump may overheat the Mercury outboard engine. In fact, this would happen in a short time as you start running your boat. To a severe extent, your boat engine may also get on fire with time.

Can a faulty fuel pump cause the Mercury outboard engine to stall?

Yes, a faulty fuel pump would definitely cause stalling of the Mercury outboard engine. You may even be unable to start your boat engine at times. Even if you do so, your boat engine would stop often while running.

How often do I replace the Mercury outboard fuel pump?

You do not need to replace the Mercury outboard fuel pump very often. On average, the replacement time for this would be after every 3 years. Note that it can go even more than that which could be up to 7 years.

Final Words

You now have a detailed idea about addressing the Mercury outboard fuel pump symptoms. We believe you can now easily fix the issues by reckoning the symptoms.

So, this brings us to the end of the article where we have seen the main symptoms are sputtering, overheating, and gas-guzzling. While you see any of the symptoms, you need to remember one thing about it.

That is, never be late to work on the symptoms to resolve the issues rather than being quick on them. Or else, the condition of your outboard engine would deteriorate in no time. We wish you good luck.

Similar Posts