Removing bad fuel from the marine fuel tank helps stop fuel contamination and prevents a boat engine from getting damaged.
Water, algae and debris like sludge or varnish can get into the fuel tank causing the fuel to go bad and this can create problems for the boat.
The instructions below apply to both diesel and gasoline boat engines and both inboard and outboard motors.
To remove bad fuel from a boat fuel tank:
- Use A Suction Pump To Drain Bad Fuel From The Boat Fuel Tank
- Disconnect The Fuel Lines, Spray Fuel Tank Cleaner Into The Boat Tank & Rinse With Water
- Use A Suction Pump Again To Pump Out The Dirty Water Into A Bucket Or Container
- Reconnect Fuel Lines & Fill The Boat Fuel Tank With New Clean Fuel
- Dump The Bad Fuel In A Waste Fuel Disposal Location
These steps will ensure the bad fuel is removed from the boat fuel tank and disposed of in a safe and secure way.
Step 1: Use A Suction Pump To Drain Bad Fuel From Boat Fuel Tank
The first step is to get a suction pump and drain out all the bad fuel.
To drain out the bad fuel from the fuel tank:
- Use a suction pump: Using a manual suction pump will pump the dirty and bad fuel out of the marine fuel tank. For very large boats like super yachts or ships, a motorized suction pump will be needed as there is a much larger fuel tank to empty and a motorized pump will speed up the process
- Make sure the fuel tank is completely empty: Ensure every drop of dirty and bad fuel has been removed into a bucket or container
- Use a bucket or container that can be sealed: A sealed container will help prevent spillage & prevent environmental harm or foul odors
- Use a bucket or container that has the capacity to store all of the bad fuel: Use a bucket or container that is capable of storing all the bad fuel in it. It can get messy if using multiple buckets. For example, a 12-liters fuel tank will need a bucket capable of holding a minimum of 12 liters
For most recreational marine vehicles, removing the bad fuel with a suction pump should take approximately 10 to 20 minutes at most to complete.
For larger boats like ships or super yachts, removing bad fuel with a suction pump can take between 30 minutes to over 1 hour to complete.
The suction pump will remove all the bad fuel from the boat fuel tank. Get a sealable container or sealable bucket to collect all the bad fuel safely.
Step 2: Disconnect The Fuel Lines & Spray Cleaner Product Into Boat Fuel Tank
The second step is to disconnect the fuel lines, spray fuel tank cleaner into the fuel tank and rinse it with water.
It is very important that you disconnect the fuel lines first to ensure no engine damage.
Using a boat fuel tank cleaner will:
- Remove any dirt left from bad fuel: The cleaner will help dissolve any residual dirt left from bad fuel in the fuel tank and ensure it's clean when putting new fresh fuel into the marine tank
- Dissolve any trapped sludge, dirt or varnish: A fuel tank cleaner will help dissolve any trapped sludge, dirt or varnish and ensure any new fuel does not turn bad
- Prevent future fuel contamination: A fuel tank cleaner will help prevent any new fuel from being contaminated as the dirt will be removed
Use a marine-grade fuel tank cleaning product when removing dirt from the fuel tank.
Do not use any product that is not marine grade as it may hard the fuel tank or the boat engine.
The top fuel tank cleaner products list will help with choosing the right cleaning spray to use.
After spraying the fuel tank with fuel tank cleaner, rinse it with water.
This will loosen up the remaining dirt and the soapy cleaner used to clean the tank.
Also, check the fuel lines for any clogging or dirt and ensure the fuel lines are clean and unclogged.
Spraying the fuel tank with a cleaner will help remove any dirt built up with the bad fuel. This will prevent future fuel contamination.
Step 3: Drain The Dirty Water From Boat Fuel Tank Into A Container
The third step is to use the suction pump again to remove the fuel tank cleaner and dirty and soapy water.
Using the suction pump again to pump the dirty water and cleaning product out of the boat fuel tank and into a bucket or container will:
- Ensure the new boat fuel won't be contaminated: A clean fuel tank means the new boat fuel won't go bad or get dirty. Pumping out the soapy cleaning water is important to ensure future fuel contamination won't occur
- Help with engine performance: With no dirty or bad fuel in the tank, the engine will run better
- Ensure the fuel tank is clean: Removing the fuel tank cleaning product and soapy and dirty water will ensure the fuel tank is spotless and ready for new fuel
This step should take no longer than 5 to 10 minutes to complete for recreational boats like speedboats, pontoons, deck boats and motorboats.
For larger boats like super yachts, this process can take between 30 minutes to 1 hour
Drain the cleaner product and dirty soapy water into a sealed bucket or container. Having the fuel tank clean will help prevent new fuel from going bad or getting contaminated
Step 4: Reconnect The Fuel Lines & Fill The Boat Fuel Tank With New Clean Fuel
The fourth step is to reconnect the fuel lines to the fuel tank after they have been cleaned and fill the boat motor with clean fuel.
Make sure the bad fuel, dirt and soap from the cleaner has been fully removed from the boat fuel tank before reconnecting the fuel lines and filling it with clean fuel.
Reconnecting the fuel lines and filling the tank with clean fuel should take no more than 5 minutes to complete.
For larger boats like super yachts, it should take approximately 20 to 30 minutes to complete.
Step 5: Dump The Bad Fuel In A Waste Fuel Disposal Location
The fifth step is to dump the bad fuel in a sealed container in accordance with the hazardous waste fuel disposal instructions given by a dump or local marina.
After fully removing the bad fuel from the marine fuel tank, it must be safely disposed of.
To safely dispose of the bad fuel:
- Contact a local marina or disposal center: Usually a local marina will have all the information required to safely dispose of the bad fuel from the boat. Contact them or travel with the fuel waste to their location
- Ensure the bad fuel is in a certified sealed container: Ensure the bad fuel and dirty water is in the correct and certified container so no leaks occur. This will prevent fuel leaking in your vehicle as you transport it to the waste site
Some disposal centers might not take the bad fuel waste if it's not in a proper certified and sealed fuel container.
Contact them before transporting the waste to ensure the local safety requirements are met.
Typically, there will be a fee for dumping the bad fuel. In most instances, it won't cost more than $20 to dispose of the fuel.
Contact a local disposal center or marina for safe disposal instructions of the bad fuel. Then, follow those instructions and dump the bad fuel in accordance with those instructions.
Products Needed To Remove Bad Fuel From Boat Fuel Tank
To remove bad fuel from the boat fuel tank, the products needed are:
- A certified sealable fuel container or bucket: This is to ensure the safe transport of the bad fuel to a disposal center
- A fuel suction pump: A manual or motorized suction pump will help pump out the bad fuel from the boat fuel tank
- A boat fuel tank cleaner: This will help remove dirt and prevent any new fuels from going bad
- A pair of gloves: This is to protect your skin from any chemical irritants
With these products, you will be able to safely dispose of bad and dirty fuel.
Get a fuel suction pump, a pair of gloves, a certified sealable container, and some boat fuel tank cleaner to safely remove bad fuel from the boat fuel tank.
Professional Fuel Removal Service
Another option for removing bad fuel from a boat fuel tank is to hire a boat fuel tank cleaning service.
Hiring a professional boat fuel tank cleaning service will:
- Ensure the bad boat fuel is removed safely: A professional service will remove bad fuel safely as they will have experience
- Prevent engine or fuel tank damage: A professional company will know the do's and don't s of removing boat fuel from specific boat types. This will help prevent engine or fuel tank damage
Professional boat fuel tank cleaning costs between $45 and $300.
A professional fuel tank cleaning service will remove all the bad fuel and clear out the fuel lines and fuel filters too.
To find professional boat fuel removal services, simply contact your local marina for contact details for these services.
You can also find these boat fuel removal services on Craigslist or Facebook marketplace.
An alternative option for removing bad fuel is to hire a professional marine fuel removal service to do the work. Contact your local marina for information on where to find these services.
Frequently Asked Questions About Removing Bad Fuel From The Fuel Tank
Below are some popular and common questions about removing bad fuel from a marine tank.
Is It Difficult To Remove Bad Fuel From A Boat's Fuel Tank?
No, it is straightforward and easy to remove bad fuel from a boat's fuel tank. It can be completed in 5 simple steps.
What Are The Advantages Of Removing Bad Fuel From The Boat's Fuel Tank?
There are many advantages of cleaning a boat fuel tank and removing bad fuel including improved engine performance and more importantly preventing engine damage.
How Long Does It Take To Remove Bad Fuel From The Boat's Fuel Tank?
It takes 20 minutes to 30 minutes to remove bad fuel from most common boat fuel tanks.
For larger boats like a ship or super yachts, it can take between 30 minutes to an hour to remove the bad fuel.