How To Detect Bad Gas In Boats Fuel Tank? (Explained)

The most common reason behind a boat’s engine failure is having bad gas or fuel in the boat’s fuel tank. The Bad fuel prevents your engine from operating smoothly and eventually forces the engine to shut off.

This article will help you to detect whether you have bad gas in your fuel tank and if you have, then how to get rid of bad fuel issue:

What Sign You Should Look For To detect Bad Gas/Fuel In Boats?

You need to know the most common and clear sign to detect bad gas in your boat fuel tank and the most obvious sign of bad gas is when you notice that your boat is running rough or stalling frequently and idling.

Symptoms Of Bad Gas In Boats Fuel Tank

What Are The Symptoms Of Bad Gas In Boats Fuel Tank?

The symptoms of bad gas in boats are usually related to the following indications:

1. Engine Idles, Runs Rough Or Hard:

The easiest way to avoid such commotion is to keep an eye on your engine’s performance to detect any symptoms.

If you encounter that your boat engine stopped smoothly starting like before and started rough or hard starting, or even frequently idling, check the gas condition first.

2. Appearance Becomes Darker & Smells Bad:

When your boat’s gas or fuel becomes bad, you can confirm simply by checking on its appearance. Most people do not frequently check on their gas appearance, and that’s when the problem occurs.

If you notice that the gas has become darker than usual and turned into dark amber color, it is another obvious indication that your gas has gone bad.

Also, when your gas becomes older or bad the natural odor of gasoline will turn into the smell of the pungent varnish.

3. Stalls During Acceleration & Decreases Fuel Economy:

Another symptom that you may experience when you have bad gas in your fuel tank is the rapid reduction in the fuel economy level.

If you observe closely, you will see that your boat’s motor started stalling frequently and especially, during acceleration.

4. Engine’s Light Illuminating:

In general, the boat’s engine light illuminates when you have old or low-quality gas in your boat.

Therefore, if you ever notice that the motor or engine’s light is suddenly illuminating, it can be a sure indication that you need to check your gas.

Whenever you encounter or notice any of the symptoms mentioned earlier, make sure to investigate in your gas or fuel tank whether the gas went bad or not. 

How Should You React If You Detect Bad Gas In Boats Fuel Tank?

Now that you have successfully detected that you have bad gas in your boat, it is time to get rid of that as soon as possible, or else it can cause severe engine damage so, act quickly.

To fix the problem, follow the given instructions below –

Fixing Older Ethanol-Free Gas:

If you used ethanol-free gas, which has become older than almost one year and causing trouble in the engine’s performance, you can still fix the bad gas without changing.

For fixing your older ethanol-free gas, all you need to do is add a good amount of fresh gas with the left-out older gas. That fresh added gas will clear the older gas to make it better.

Note that this solution will only work for ethanol-free gas. Also, remember not to use even ethanol-free gas for more than one year, which can cause severe damage, and better avoid using ethanol-free gas older more than six months.

Pumping Out With Electric Pump Or Primer Bulb:

If you have regular gasoline in your boat’s fuel tank, you can use either an electric pump machine or a primer bulb to drain out the bad gas from the tank.

If you need to remove a large amount of gas, the electric pump machine will fit perfectly for you. But if the fuel or gas amount is small, better to use a primer bulb.

Also, the using process of both devices is super user-friendly, just have to attach the machine to your fuel pump outlet.

Siphoning The Bad Gas:

If you have a small volume of gas to remove, then siphoning is simpler and quicker trick to use. But it can be better only if you can reach the bottom of your boat’s fuel tank with the tube.

For siphoning, disconnect the hose from the primer bulb’s engine side and put cans under your fuel tank.

Then, you need to hook up a hose from the primer bulb’s engine side and run that through the garboard drain plug to the outside of your boat. Now attach the other end of the hose tube in the gas can and use it.

Are Removing Bad Gas In Boats Typically Expensive?

Not really, since all you have to do is either clearing your gas (only applicable for ethanol-free gas) or drain out the bad gas from your boat’s fuel storage.

Especially if you are doing that job by yourself, besides the pumping machine or primer bulb, tube, and other required essentials, there is no extra cost involved.

But in case you hire a professional or take the service from any boat’s servicing center, that professional servicing is available at moderate pricing too.

How Often Should You Check Boat Gas/Fuel?

In general, after filling up the fresh and pure gasoline, the new poured gas tends to lose combustibility around 50 to 90 days of use because of vaporization and oxidation.

Also, remember fresh gas will remain in perfect condition to run the engine smoothly for a maximum of 120 days.

Therefore, after 120 days of use, you should change or clear your gas unless you want bad gas to harm your boat engine.

The Verdict

Having bad gas in the boat can be the worst nightmare since it directly damages the boat’s engine so, you should always keep a close eye on the condition of the gas.

Also, whenever you encounter that your engine struggles in acceleration, frequently stalls or shuts down after a rough start, without wasting any second, check your gas condition.

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