Smelling fuel on a boat can be a serious issue very quickly. Knowing what to do and what your options are is extremely important!
What should I do if my boat smells like fuel? If you smell fuel on your boat. Shut off the fuel if possible and locate the leak. If the leak is along the fuel hose, repair it before using the boat. If there is fuel in the bilge, the fuel is probably coming from the fuel tank.
When the fuel tank is leaking there could be other issues that will need to be dealt with. Here are a few options about what to do next.
What Kind of Fuel Leak Are We Dealing With?
There could be multiple different scenarios in which you could smell fuel on a boat.
- A fuel filter could have rusted through and is leaking fuel into the bilge.
- A fuel line could have a hole in it and leaking fuel into the bilge.
- The boat fuel tank could have a hole in it and be leaking fuel.
- There could be a leak from the fuel sender or pick-ups on the fuel tank which are leaking fuel when the tank is full.
- The fill hose to the fuel tank could be leaking.
- Or your buddy could have filled up the rod holder with fuel when he was pumping it! (This is actually more common than you think! I have actually been working in a bilge on a bilge pump when the owner decided to do this. He was actually surprised when I told him that we could no longer finish the job because we could not heat the heat shrinks on the wires with so much fuel in the bilge without blowing the boat up!)
Figuring out what kind of leak we are dealing with is going to be very important in deciding what exactly are our options. Then going about fixing the issue and getting the boat back in service.
Locating the Boat Fuel Leak
Locating the fuel leak is the first step we need to take after figuring out what kind of leak we are dealing with. Performing a visual inspection is a great place to start.
This will consist of following the fuel lines from the engine down to the fuel tank and looking for anything that is suspect.
Here is an article we wrote about why an outboard loses prime and how to fix it. In this article we go through a good process for checking over the fuel lines and most of the common components that you will encounter that are in a boat with an outboards fuel system.
Following those fuel lines and visually looking at the lines will get us in the right direction and if there is a fuel leak coming from there, then we will be able to locate and fix it without major issues!
What To Do if the Leak is Not in the Fuel Hoses?
If we follow all of the fuel lines and look over everything without any issues (and confirming that our buddy didn’t spill fuel all over the boat the last time they put fuel in it), but there is still fuel sitting in the bilge, then we are going to be suspecting the fuel tank.
This is where everyone gets wild and gasps! Don’t get to excited just yet, we still have options!
First, we need to confirm that it is the fuel tank that is leaking.
How To Pressure Test A Boat Fuel Tank?
Pressure testing the boat’s fuel tank is going to be the trick to confirming the fuel tank and then looking over the options. In order to pressure test the fuel tank, we need to close off all of the ports that are on the tank.
***NEVER PUT MORE THAN 3 LBS OF PRESSURE INTO A FUEL TANK! THE TANK’S WELDS COULD SPLIT OR YOU COULD BLOW HOLES IN THE WEAK SPOTS OF THE TANK!***
The best way to close off the ports is to know how many there are.
- There is the fill port.
- The boat fuel tank vent port.
- Then the pick up tube ports, sometimes there are more than one.
The best way that I have found, to close off the fill port, is to go to your local hardware store and purchase an inflatable pipe plug.
Normally a 2″ plug will work for most tanks. If your fuel tank has a 2″ fill hose, sometimes depending on the test ball, it won’t securely plug off the hose. Make sure you get what will work for your tank.
Then we take a pair of hose pinch pliers and using these we can clamp off the vent hose.
The last thing to do is to disconnect the fuel pick up hose and then make a fitting to attach it to an air pump. For this, we will get a piece of 3/8″ hose or 5/16″, depending on the pick up tube on your tank.
Then, attach a pressure tester hand pump to the hose. (I’m not a fan of that pump, I actually really, really, strongly, dislike that thing. It takes forever to pump up, the handle moves around and can pinch your hand. Just this way you can see and get an idea of what I’m talking about.
You don’t need to go out and buy some super expensive pump either. Just something that will get you 3 PSI!
If there is more than one pick up, take the hose off the other one and then install a short piece of hose with a bolt stuck in the end of it and place a hose clamp on it. This will seal off that port.
Once you have all of the ports plugged off, pump the pump up to 3 PSI and see if it moves. If you lose any pressure, take some soapy water and spray around the fill, the vent port, also the hoses and pump at the pick up fittings.
If there is air coming out of the vent, disconnect the hose and do the bolt trick there too. Check the fuel sender just to be sure.
Then, if there isn’t any air coming out of any of these places, but you are still losing air, most likely you will see fuel start to accumulate in the bilge and you will get a strong smell of fuel. This is a tell tale that the tank has failed and there is a hole somewhere on the tank!
What Are the Options if the Boat Fuel Tank is Leaking?
This is the point where we can get super expensive, cheap and quick, or just whack and pack that bad boy to get back on the water. Depending on the boat and the budget there are only a few options to safely do this.
I do know of people that have successfully repaired some fuel tanks. They have made some patch work out of it and/or have rigged it back together.
This may be an option for some to figure out a way to repair a boat fuel tank without replacing it. But as for me and my advice, in the situations that I deal with, we’re talking about offshore, ocean going, deep blue boating.
Not back on the river, the weekend lake warrior, or the pond fisherman.
So, yes you can patch some tanks and fix them. But I can’t recommend this because my concern is safety and when people are taking 21′ center consoles 30 miles offshore in 2500′ of water. We want to make sure we get back home.
We can’t have any fires, explosions, major leaks, or catastrophes where we are floating off into the night at the mercy of the waves.
What Are the Cheap Options?
The cheapest option available is go ahead and abandon the main boat fuel tank for the time being.
What you can do here is to use a remote tank. Get a large remote fuel tank that can hold 20-30 gallons of fuel and place that tank in the back of the boat. Hook that up and get fishing!
The advantages of this is that you can get back on the water in no time! It’s a quick deal, hook up the fuel hose, fill it up, prime up the primer bulb, start the engine and get going!
You can get this done in a matter of a weekend depending on if there is a fuel tank available in your area.
The disadvantage to this is that if you don’t have a lot of room in the transom area of your boat, then this will be challenging. Another disadvantage to this is that you have limited distance!
Being used to having a larger tank in a main boat fuel tank holding 60-80 gallons of fuel, this will be cutting you down a lot. But for the time being if needed, this will be a quick and safe alternative to the other options.
What Are Some Reasonable Options?
Short of replacing the main fuel tank and having a remote boat fuel tank in the transom area. There really aren’t very many options. Sadly, when a boat’s fuel tank gets to the point of needing to be replaced, you really are stuck replacing it. I know, sadface.
However, depending on the circumstances, if the failure of the fuel tank is at the top of the tank and there aren’t any issues with water getting into the fuel, then holding out and saving up can be an option.
You will need to figure out how much fuel is too much fuel. Then, just stay below that mark on your fill ups, as to keep fuel from spilling out of the failed location of the tank.
As far as other circumstantial reasonable options, there aren’t many. The problem with a boat fuel tank is the water issue. You don’t want to waste tons of money dealing with water in the fuel, causing problems with the engine.
What is the Inevitable Sometimes Expensive Option?
Then looming around is the real fix to the issue. That is the boat fuel tank replacement options. Which, depending on the brand and style of your boat, can get really expensive, or not. If the fuel tank is accessible, then replacing it won’t be that bad.
The issue with most boats is that the entire console has to be de-rigged and removed from the boat.
Working and talking mainly about center console boats. Most of them have the fuel tanks positioned completely under the console and back deck. Where the deck access, (if there is one) is partially under the console or completely under the console.
Having to pull the console out of the boat to remove the tank, that is where it gets expensive.
Some boats are nice though, where you can actually remove the access to the tank and just pluck the tank out of the boat. But this is not the most common situation. The expensive part is the time intensive labor in de-rigging and removing the tank. Then re-rigging all of the components.
Things to Consider Before Embarking On Tank Replacement
A quick note on what you should consider before replacing your boat’s fuel tank.
- What is the cost going to be: If the cost of taking on the tank replacement out weighs the actual value of the boat. You might consider searching around for another boat. Depending on the engine situation and over all condition of the boat. You don’t want to sink thousands of dollars into a tank replacement and have been able to find a better boat without the issue, for the same amount!
- What is the structural condition of the boat: Take note on the failure of the fuel tank. You might check out the transom and the stringers before doing the replacement. If the stringers are beginning to rot and the transom is getting soft, then the tank replacement will get to be way more expensive than you originally planned for. Make sure you survey these two main structural points of the boat first.
- How much do you really love your boat: This is a good point that a lot of people over look. Some people get so attached to a boat that they never look into what other options are out there. The functionality and enjoyment of a boat comes in many different shapes and sizes. After spending some real time boating and figuring out what kind of boater you are. Whether a weekend sandbar person, a real fisherman, a sunset cruiser, a diver, or a water sports kind of person. You should get to know what you want out of your boat and whether or not this is a good time to change it up and explore different avenues and possibly even a new/different boat!
How to Remove the Boat Fuel Tank
Removing a boat’s fuel tank is so circumstantial to each individual boat that you can’t have a one size fits all approach to this. For a general rule of thumb, removing the tank begins with getting to the tank.
If you can access the tank, great! If not, think about how much has to be done in order to get to it.
In the event that you have to remove the console, get to de-rigging and labeling all of the wiring that goes down into the deck; then, this may be time to think of cost/time of labor versus value of the boat. However, if you decide to proceed then read on…
Now that we have gotten to the tank. Most boat fuel tanks have been foamed in. Here is an article that we have written on foaming in a boat fuel tank, and what our thoughts are on the subject!
If the fuel tank has been foamed in. Then the foam will need to be dug out from around it. Then the fill, vent, and pick up hoses will have to be removed.
It is important to note, at this point the fuel fill hose and sometimes the vent hose, will need to be cut off the tank and end up being replaced. Otherwise, it will end up being too short.
Over time the hoses shrink and basically weld themselves to the ports. Thus, making it impossible to remove them without cutting them. So account for hose replacement.
Then with the hoses off, disconnect and remove the fuel sender with the tank grounding wire. Then we can attach a chain to the tank. Or, a lot of times what we find works great is installing an engine bracket bolt. Like the type of bolt used for attaching the engine to the transom.
Then, stick that into the sender hole and pick the tank up with the bolt in the tank and a chain in the middle of the bolt.
You will need a forklift or a come-a-long / cherry picker / something with some real force to pick the tank up out of the boat.
Over time, the foam that is underneath the tank creates a suction onto the tank. This makes it impossible to remove the tank by hand. Most of the time the boat gets picked up from whatever it is on, just by the tank. That is before it pops and releases from the boat.
That’s it in a nutshell! That is removing the tank! Then installing the new tank will be another chore. It is a lot simpler to install the new tank. There are a few pointers back in our article about foaming in a boat fuel tank, for installing the tank and how to secure it. Then just put everything you removed, back into place!
Hopefully this gives you some more insight into what you are about to embark on if your boat smells like fuel!