Left the boat for a long time and worried about the fuel condition inside it? Unless you know the symptoms of old gas in your boat, you can’t just toss the gasoline away. So, what are the symptoms of old or bad gas in a boat?
Symptoms of old or bad gas in a boat are either the boat will have rough idle, reduces fuel economy, stalls frequently while accelerating (fails to start). You can also tell if gasoline is bad by its appearance. If it’s darker than usual or has a sour smell, or has water in it, it’s probably bad.
Bad gasoline is the most common cause of boat engine failure. Identifying and avoiding bad gasoline will help keep all gas-powered things running smoothly. However, unless you start the boat or visually saw the gasoline, you can’t really tell whether the gas in the boat is bad or not.
Another important factor is what type of gas you have used in the boat, ethanol gas (E10 gas) or ethanol-free gas. The other factors that affect the gas are climate, engine type, and stabilizer is added or not. Without further ado, let’s see the symptoms of old or bad gas in the boat in a detailed way.
What Are The Symptoms Of A Old (Bad) Gas In Boat?
Smells Bad (Like Varnish)
Gas contains volatile compounds that allow it to burn. As these compounds evaporate, gas becomes less combustible and eventually turns into a gummy varnish-like substance. When this happens, gasoline no longer smells like gasoline; it smells like pungent varnish.
Many people like the smell of gasoline, and it’s actually not that weird to like the smell of gasoline. Benzene is added to gasoline to increase octane levels, which improves engine performance and fuel efficiency. Benzene has a naturally sweet smell that most noses are particularly attracted to.
Benzene is so pungent that the human nose can detect it if there’s just 1 part per million in the air we breathe. If you smell something other than gasoline, it’s a symptom of bad gas. Whether to remove the gas or not depends on so many factors. Check the “how to deal with old gas in boat” subtopic below to know more.
Color Of The Gasoline Becomes Darker
Gasoline, regardless of the dye used, will have a transparent-like nature. And that’s the best kind of gasoline to use. As time goes by, the color of the gas will change. This is usually caused by oxidation. Oxidation is the process by which a substance (gasoline in this case) combines with oxygen.
As gasoline gets older, it will change from its original color to a darkish color, eventually turning into a deep amber color. As gasoline degrades further, it goes from clear in color to look darker. If you see a color change in the gas, it’s a symptom of an old (bad) gas.
Forms Water Inside The Fuel Tank
This particularly applies to ethanol gas (E10 or E15 gas). The ethanol in gas attracts moisture, and weather changes cause condensation in gas tanks, forming water inside the gas tank if the gas is left for a long time. Water is heavier than gas and will form a separate layer below the lighter-weight gas.
This is known as phase separation (gasoline at the top, water at the bottom inside the fuel tank). Water, of course, does not work too well as a fuel in an internal combustion engine. It will cause hard starting and rough running until it’s removed from the whole engine system.
It can also contribute to the internal rusting of the gas lines and tank. This could be a nightmare for the boaters. You can reduce the chances of water contamination by keeping your boat’s gas tank as full as possible, especially if the boat is going to be left idle for an extended period.
Boat Won’t Accelerate As It Used To
The quality of the gas that is used in your boat is a direct consequence of your boat’s acceleration power. Since accelerating a boat requires a sudden burst in power, more combustions are needed, and more gas is used to get you moving in the waters.
If you throttled forward and did not accelerate right away, then you are experiencing hesitation from the engine. This hesitation could be the result of bad fuel in the internal combustion chamber. It will take your boat a few seconds to respond to the throttle movements before it accelerates, or it won’t accelerate at all.
The faster you try to go; the more apparent this symptom will be. Bad or old gas can directly affect your ability to accelerate.
Reduced Fuel Economy
If it seems like you’re filling up your boat more than usual, it may be because of bad or old fuel in the tank. Bad gas is a term used for gas that does not combust as efficiently as most gas sources. Boats and other vehicles use carbon-based combustions made from burning gas to move.
Thus, if you have bad gas in your boat, your boat may not be able to get you as far as normal. So, if you start to notice that you are burning gas faster than normal, it will most likely deal with the bad fuel unless you have a fuel filter or fuel pump or other problems that restrict the fuel flow inside the engine.
Related post – What are the symptoms of a bad boat fuel pump and Fuel filter? Check those two articles to know all the symptoms of a bad boat fuel pump and fuel filter in a detailed way and how they can restrict the fuel flow into the engine.
Engine Sputters Or Stalls While Starting Or Running
One of the most common causes for a boat engine to sputter while starting is due to the issue with the fuel system; it can be a filter, pump, and injectors, or fuel itself is bad. These three vital components work together to ensure fuel flows smoothly from the fuel tank to your engine.
If anything interrupts the fuel flow or if anything other than fuel gets into the engine (like water or bad fuel), the boat engine will surge or stop while running. This could result in your boat not having enough combustible ingredients to continue to propel boat.
Thus, if you have bad gas in your boat, your boat will sputter or stalls while running so, if you start to notice that, it will most likely deal with the bad fuel unless you have a fuel filter or fuel pump or other problems that restrict the fuel flow inside the engine.
Related post – Boat won’t start and just clicks? Check this article to know more about the reasons why the boat won’t start.
How To Deal With Old Gas In Boat? Dump It Or Use It
If you post the same question in the forums around, you will see the majority replies to ditch the gas and start with fresh gas. Some will say there is a difference between $100 fuel waste vs. $1,000 motor damages, etc. So, should you use the old gas in your boat?
You can use the old gas in a boat if it is ethanol-free and a little over a year old. But you should add fresh gas to the tank before starting the engine because the left-out gas can gum up the fuel system. The fresh fuel will clear it right up. However, ethanol gas is no good for more than 6 months.
The factors that affect the gas are climate, type of gas, engine type, and stabilizer is added or not. Old fuel does not burn well. The engine might not start, accelerates less, or it will putter out. The oil keeps the system lubricated, and the fuel just causes the fire to move the cylinders.
If the gas is 2 years old or more, just obliterate the gas and fill it with fresh gas (even if stabilizers or octane booster are added, a 2-year-old gas is not worth the risk). That being said, we will now see how to deal with old gas in the boat in a detailed way.
Ethanol Free Gas Will Be Good For A Year
If it is ethanol-free gas, then BINGO, you need not worry “much” about it. The only thing you need to be concerned about is, “How long has that gas stayed in the boat?”
You can use a 1-year-old ethanol-free gas without any concerns. But you need to mix some fresh gas in the tank (50% fresh (high octane) gas or more) and then start the boat. If you live in Florida or such regions where temperatures are a bit high, it might struggle, but it will pick up sooner or later.
Above one to two years old ethanol-free gas, it really depends on the climate and whether stabilizer is added or not. If the stabilizer is added, you can use the gas but add some fresh gas in the tank (50% fresh gas or more), and then start the boat. But still, it a bit risky in humid climates.
Remove the gas completely off the tank if it is more than 2 to 2.5 years old. The bigger problem might be having the gas sit in carburetors for that long and foul the jets. So if you have gas left for more than 2 to 2.5 years in the boat, just remove it and use it in lawn mover, truck, car, etc., but not in a boat.
Non-Ethanol Free Gas Will Be Good For 6 Months
Ethanol gas (E10 or E15) is no good for more than 6 months. If a stabilizer is added to it, you can extend its life close to a year. If it is older than that, just remove the old gas completely and fill it up with fresh gas because ethanol can attract moisture, forming water inside the tank.
Stabilizers do a good job of preventing carbs from gumming up for a little over a year. But it’s not that great at maintaining octane ratings, preventing fuel breakdown, oxidation, contamination, etc., for more than 1 to 1.5 years. Adding octane boosters also not recommended with non-ethanol-free gas.
That being said, the E10 gas will keep absorbing water over time no matter what you add to it, and eventually, you will have phase separation, which will destroy your engine. If you don’t have E10 and add a stabilizer, you could probably go a pretty long time than E10 gas.
IMPORTANT – If you decided to use the old gas in your boat (regardless of Ethanol or Ethanol-free gas), don’t forget to add fresh gas because the left out fuel can gum up the fuel system a bit, but fresh fuel will clear it right up.
How To Remove The Old Gas Out Of The Boat?
Pumping out the old gas from the boat could really be a simple task. At the same time, it could be a challenging task. By using some simple tools, you can do it very easily.
You can pump out the old gas off the boat using an electric pump or primer bulb attached to the fuel pump outlet. An electric motor will be good for pumping out large volumes and a primer bulb for small volumes. Siphoning the fuel is a lot easier process if you can reach the tank bottom with the tube.
First, you should decide how you want to take the gas out of the boat, with the help of an electric pump or by siphoning process. Siphoning is a simple trick to remove the gas easily out of the boat unless you want to remove large quantities, which will take more time.
An electric pump will do the job well regardless of the quantity you want to get it out. A small 12-volt pump is sufficient for pumping the fuel out completely, like this 12-volt gas transfer pump from the gas tapper (linked to Amazon), which takes out huge quantities quickly.
Otherwise, if you want to take out small quantities, a small primer bulb set up (linked to Amazon) will do the job quite easily, and you can save $30 or more without buying an electric motor. Check this very helpful video below on how to siphon the gas out of the boat easily.
The best way is to connect the siphon pump to the FUEL PUMP OUTLET to get the fuel out easily without leaking or other concerns.
The Key Takeaways From The Post
If the boat has a rough idle, stalls frequently during acceleration, or fails to start at all, your gas has gone bad. You can also tell if gasoline is bad by its appearance. If it’s darker than usual or has a sour smell, or has water in it, it’s probably bad.
Bad gasoline is the most common cause of boat engine failure. Identifying and avoiding bad gasoline will help keep gas-powered equipment running smoothly.
The factors that affect the gas are climate, type of gas, engine type, and stabilizer is added or not. Old fuel does not burn well. The engine might not start, accelerates less, or it will putter out. If the gas is 2 years old or more, just remove the gas completely and fill it with fresh gas.
