Proper Fuel Disposal

Fuel is considered bad when it ages, oxidizes or has been contaminated with water, and once it’s bad it doesn’t vaporize and burn properly. This inefficiency can cause problems ranging from hard starting to engine knock to poor performance. It can also cause damage to the engine and fuel system.

Researching the condition of your fuel, removing bad fuel and repurposing it are the ways to properly address a bad fuel issue. Let’s call it the three Rs.

If your boat seems to be performing poorly due to bad fuel, start by checking your fuel filter/separator for water and/or particles in the fuel. Pour a sample of the fuel into a container, and the fuel will float on top of any water. Particles in fuel can come from many sources, but when associated with bad fuel, they are likely gum or varnish deposits from oxidation. Wave your hand over the container to get a whiff of the fuel. Bad fuel smells like varnish. If you see particles or smell something amiss, confirm your suspicions by running a fuel line from a portable tank with fresh fuel to your engine to see if it performs better.

Before deciding to remove bad fuel, look at your fuel gauge and compare it to the capacity of the tank. You need to be able to transfer that amount of bad fuel to a disposal facility in containers that can safely hold and transport it. Be sure to use containers you don’t need back, because a facility will not return them. If you find cheap used containers, fill them with water first and make sure they don’t leak before transferring fuel to them.

A siphon or fluid pump is your best bet to transfer fuel to the containers. You can find a transfer pump at your local hardware or home-improvement store, usually in the lawn and garden section, for less than $20. They look like small bicycle pumps with two hoses. The pumping action draws fluid from the tank into the intake hose and forces it through the output hose into a container. Wear protective gloves, eyewear and headgear when you’re transferring the fuel. Clean up any spilled fuel with rags, and properly dispose of them at the collection facility.


Pack the containers securely in cardboard boxes to prevent them from tipping or spilling during the drive to the facility.

Some old fuel can be mixed with fresh fuel and used in other applications such as gas-powered lawn equipment and oil/gas heaters.

If the fuel is too bad to use in any other application, you need to find a hazardous household waste (HHW) collection facility to legally and properly dispose of the bad fuel. An HHW is any consumer product that, if improperly discarded, can be dangerous to humans and the environment. Public and private institutions fund facilities for the collection and disposal of fuel and other HHWs. For example, the state of California has set up permanent HHW collection locations called S.A.F.E. (Solvents, Automotive, Flammables and Electronics) centers. To locate a collection facility in your area, check the websites of the solid-waste management departments of your state and local governments. If your area does not have a permanent HHW collection facility, you may be able to find one-day collection events, which are typically posted in libraries, community bulletins or newspapers. Automotive parts stores, car dealerships and repair shops are also good sources for information about fuel disposal.


Once you locate a collection facility, find out its operating procedures, including the amount of fuel it will accept at one time. Also, to be in compliance with Department of Transportation regulations, you want to find out how much fuel a non-commercial vehicle can carry. For example, in California, it is illegal to transport more than 15 gallons of fuel in a non-commercial vehicle.

Fuel for Thought
The best way to prevent dealing with bad fuel is to keep fresh fuel in your tank and keep water out. Buy fuel from a busy gas dock or station within a few days of a fuel delivery to ensure that you have the freshest fuel possible. Keep your fuel tank(s) full to prevent condensation from forming, especially during the off-season or periods of low use. Research fuel additives or treatments to see if they are appropriate for the make and model of your engine. If recommended, add the appropriate amount for your fuel capacity at the time of your fill-up. If possible, run your engine once or twice a month to keep the fuel system clear and to circulate any additive or treatment through the fuel system.

Also, look for points of entry for water, the most common of which are the deck fill plate and the tank air vent. Make sure that both are secured flush against the hull and that all hoses and fittings are secured.

Since fuel is one of the lifelines of your powerboat, regular maintenance and high-quality fuel will help keep your engine healthy. Your engine will spring to life every time you turn the ignition key.


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