How to Drain a Boat Fuel Tank?
Last Updated on September 29, 2022
Assuming you need to drain the fuel tank because you’re selling the boat or it’s going into storage for the winter, here are a few tips. First, if the boat has been sitting for a while and you haven’t used it, make sure to start the engine and let it run for a bit before draining the fuel. This will help get any built-up sediment out of the bottom of the tank.
Next, find the fuel line that runs from the tank to either the engine or carburetor – this is where you’ll attach your hose. It’s important that you use a clear hose so that you can see when all of the fuel has been drained. Finally, once everything is hooked up, open up the valve and let gravity do its job!
- Locate the drain plug on the bottom of the boat fuel tank
- Place a container under the drain plug to catch the fuel as it drains out
- Loosen and remove the drain plug, allowing the fuel to drain into the container
- Once all of the fuel has drained from the tank, replace and tighten the drain plug
How to Drain Underfloor Fuel Tank
Assuming you have an underfloor fuel tank, there are a few things you’ll need in order to drain it properly. First, you’ll need a way to access the tank. This may require removing a portion of the flooring above it.
Once you have access to the tank, you’ll need a pump to remove the fuel from it. A hand pump will work fine for this purpose. Finally, you’ll need some hose or tubing to direct the fuel into whatever container you’re using to store it.
Draining an underfloor fuel tank is not a difficult task, but it’s important to do it safely and correctly. Follow the steps outlined above and you’ll be able to drain your tank without any problems.
How to Clean a Boat Gas Tank That Has Been Sitting
If you have a boat gas tank that has been sitting for awhile, it is important to clean it before using the boat. Here are some steps to take to clean the boat gas tank:
1. Remove the boat gas tank from the boat.
This will allow you to access the tank more easily and will prevent any fumes from entering the boat while you are cleaning it.
2. Inspect the outside of the tank for any dirt, debris, or corrosion. If there is any major damage, it may be necessary to replace the entire tank.
However, minor damage can usually be repaired with a little elbow grease and a few supplies from your local hardware store.
3. Empty any remaining fuel from the tank using a siphon or other suction device. Be sure to dispose of this fuel properly according to your local regulations (usually by taking it to a certified recycling center).
4. Once the fuel is out of the tank, rinse it out with fresh water several times until all traces of fuel are gone. You may also need to scrub away any stubborn residue with a soft brush or cloth.
How to Check for Water in Boat Fuel Tank
If you’re like most boat owners, you probably don’t give much thought to the fuel in your tank. After all, as long as it’s full and gets you from Point A to Point B, what more do you need to know? Well, it turns out there is quite a bit more that you should know about your boat’s fuel, including how to check for water in the tank.
Water in your fuel is one of the quickest ways to ruin an engine. It can cause corrosion and clog up moving parts, leading to costly repairs. Even a small amount of water can cause problems, so it’s important to check for it on a regular basis.
There are two main ways to check for water in your fuel tank: visually and with a moisture sensor. The visual method is pretty self-explanatory – simply open up your tank and look inside. If you see any water, drain it out immediately and dispose of it properly.
The moisture sensor method is a little more technical, but well worth the investment if you’re serious about keeping your boat in top condition. Moisture sensors are placed inside the fuel tank and measure the level of humidity present. If the level gets too high, it indicates that there is water present and will set off an alarm so you can take action accordingly.
How to Clean Plastic Boat Gas Tank
If you have a plastic boat gas tank, you may be wondering how to best clean it. Here are some tips to help you get the job done right.
First, remove the gas cap and any other removable parts.
Next, using a garden hose, flush out the inside of the tank with fresh water. Be sure to do this outdoors in an area where any runoff can be safely drained away.
Once the tank is empty of water, fill it about halfway with a mild detergent and hot water solution.
Let this soak for 30 minutes or so before draining it out again. Now rinse the tank thoroughly with hot water until all traces of soap are gone.
Finally, disinfect the tank by pouring in a solution of one part bleach to ten parts water.
Allow this to sit for at least 15 minutes before draining and rinsing once more with fresh water. Your plastic boat gas tank should now be clean and ready for use!
Cost to Drain Boat Gas Tank
The cost to drain a boat gas tank can vary depending on the size of the tank and the type of boat. For example, a small fishing boat with a 20-gallon gas tank could cost around $60 to have the entire tank drained. A larger yacht or cruiser with a 100-gallon gas tank could cost upwards of $250 to have completely drained.
The price also depends on whether you need to dispose of the old gas or if you can simply recycle it.

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How Do You Drain Old Gas Out of a Boat Gas Tank?
If you have an old boat that you’re planning on selling, or if you’ve just inherited an old boat, one of the first things you need to do is drain the gas out of the tank. This process is actually pretty simple, and it’s something that anyone can do with a little bit of time and effort.
First, start by disconnecting the fuel line from the tank.
You’ll likely need a pair of pliers to loosen the clamp that’s holding the fuel line in place. Once the fuel line is disconnected, place a catch basin underneath the tank so that any gas that drains out will be caught.
Next, use a drill to make a small hole in the bottom of the tank.
The size of the hole doesn’t really matter, as long as it’s big enough for gas to draining out. Once you’ve made your hole, insert a funnel into it so that all of the gas will Drain into your catch basin.
Allow all of the gas to drain out until only fumes are coming out of the tank.
At this point, you can reattach the fuel line and seal up your hole with some marine-grade epoxy putty or another type of sealant.
And there you have it! Draining old gas out of a boat gas tank is really not all that difficult – just be sure to take proper safety precautions (like wearing gloves and eye protection) and disposing of any gasoline properly once it’s been drained from your tank.
What is the Easiest Way to Drain the Fuel Tank?
If your goal is to completely empty the fuel tank, the easiest way to do this is to remove the fuel line from the tank and let all of the gas run out into a container. This can be a messy process, so it’s important to have a large container on hand to catch all of the gasoline. Once the fuel line is removed, simply turn on the engine and let it run until it stalls (this may take a few minutes).
Be sure to dispose of the gasoline properly once you’re finished – never pour it down the drain!
How Do You Pump Water Out of a Boat Gas Tank?
Assuming you have a boat with an internal gas tank, there are a few ways to go about pumping the water out.
One option is to use a hand-operated bilge pump. This can be done by removing the plug from the bottom of the boat and inserting the bilge pump into the hole.
Once the pump is in place, simply start pumping until all the water has been removed from the tank.
Another option is to use a siphon hose. This can be done by attaching one end of the hose to the gas tank and running the other end into a bucket or container.
Once everything is in place, simply suck on the free end of the hose until liquid starts flowing and then let gravity do its thing until all of the water has been removed from the tank.
How Do You Drain Fuel from an Outboard Motor?
Assuming you need to do this for winterization or repair:
1. Start by disconnecting the fuel line from the outboard motor. If your motor has a primer bulb, depress it a few times to get any remaining fuel out of the line.
2. Next, open the drain plug on the bottom of the engine and let any remaining fuel inside drain out. You may need to tip the engine up on its side to get all the fuel out.
3. Once all the fuel is drained, remove the spark plugs and turn the engine over a few times to make sure any residual fuel is gone.
This will help prevent corrosion inside the engine during storage.
4. Finally, mix up a 50:1 ratio of fresh gas and oil and add it to the tank.
How to Drain Fuel Tank on Your Boat
Conclusion
If you need to drain your boat’s fuel tank, there are a few things you’ll need to do. First, find the fuel shut-off valve and turn it to the “off” position. Next, locate the fuel line and disconnect it from the engine.
Once the fuel line is disconnected, open the bleed screw on the fuel filter to allow any remaining fuel in the system to drain out. Finally, close the bleed screw and reconnect the fuel line.