*Gasoline Storage Practices*
By: Tailgunner
23 March 2004


This information has been extracted from various internet resources including Standard/Chevron Petroleum and from my own personal experience. The recommendations are of a general nature, followed by recommendations and comments for some specific uses or situations.

For general storage there are four precautions that will delay the deterioration of gasoline:

    -Fill containers about 95% full.

    -Cap containers tightly.

    -Store containers out of direct sunlight in a location where the temperature stays below 80F most of the time. I have found that gasoline stored over the winter here in Alaska tends to be more stable because our average temperature is much below 80F.

    -Use a gasoline stabilizer like Sta-Bil or Pri-G

The first two actions reduce the evaporation of gasoline during storage and reduce the exposure of gasoline to air and water vapor. The 5% air space allows room for the liquid gasoline to expand if its temperature rises. Storage temperature affects storage life

I prefer to put a fuel stabilizer additive like Sta-Bil (be sure to read the directions on the container) to the gasoline regardless of how long I plan on storing it. Fuel stabilizer additives are available at auto supply stores, Walmart, some service stations and convenience stores. Follow the label directions. The best mixing is achieved when the stabilizer is added to the container before it is filled with gasoline. The stabilizer will work only if it is added to fresh gasoline; it can’t fix gasoline that has started to deteriorate. Federally mandated reformulation of gasolines to increase the oxygen content produces a mix that will survive storage as well or better than conventional gasoline. Adding oil to gasoline doesn’t change its stability. Gasoline-oil mixtures for two-stroke-cycle engines will survive storage as well as gasoline itself.

The volatility of gasoline is tailored for the range of temperatures expected in the locality where it is sold. Engines fueled with "summer gasoline" may be more difficult to start in cold weather. Gasoline that is tailored for colder climes has additional benzine added and other chemicals to increase its ability to vaporize and burn more cleanly in internal combustion engines.

Store gasoline only in containers intended for the purpose. A 55-gallon metal drum is the only container approved by the Uniform Fire Code for the storage of more than five gallons of gasoline. Be careful to not store a container of gasoline near an ignition source such as an appliance pilot light. This is important, do not store gasoline in a garage near gas fueled heaters or water heaters. Vehicles that may sit for a period of time like boats or motor-homes need special consideration to prevent driveability problems (hesitation, lack of power) which may be encountered after storage. The probable cause is gum deposits in the carburetor, on the injectors, or on the fuel filter/screen. Treating the gasoline in the vehicle’s tank with a deposit-control additive may remove the problem deposits. Deposit-control additive concentrates are available at service stations and auto supply stores. Techron Concentrate is Chevron's most effective general purpose deposit-control additive. Follow the label instructions. Follow the label directions. If driveability doesn’t improve by the time the treated fuel has been used, check the fuel filter and screen (if any) in the fuel tank for plugging.

Boat fuel tanks are more likely to be contaminated with water for obvious reasons. Water removal is particularly important for boats used in salt water and for boats fueled with gasoline oxygenated with ethyl alcohol. Salt water corrodes some metals. So does the alcohol-water layer that separates if gasoline containing ethyl alcohol is contaminated with more than one percent water. Formulation changes that have occurred in the past few years - the addition of oxygenates and the reduction in benzene and other aromatics - have made gasolines more subject to microbial growth. Even if no water is detected, add a biocide to the gasoline in the fuel tank. Follow the label directions. The best mixing is achieved if the biocide is added to the tank before it is filled with gasoline. Biocide additives are available at marinas and boat supply stores.

Small-Engine Equipment - This applies to outboard motors, jet skis, snowmobiles, and lawn-and-garden equipment. Many manufacturers recommend that their equipment not be stored with gasoline in the fuel tank. The tank should be emptied and the equipment run until the fuel line and carburetor also are empty. Both recommendations are intended to protect essential fuel system parts from gum deposits. I have a generator that I like to keep fuel in ready for use if the power shuts down. Every spring and fall I change the oil and run the generator for an hour or so to get everything up to operating temperature and use it with a load (this is important to generators). Once yearly I also change the spark plug, keeping the old one and cleaning it for rotation in next time until they are best thrown out. After checking everything out I refuel it with gasoline that has been treated with Sta-Bil and set it aside for later use. I have not had difficulty when keeping to this procedure. I use the same procedure with my snowblower, lawnmower, weed eater and chainsaw. I run each at least twice a year even if they are not needed, just to keep my confidence in starting them and in their running properly.

Equipment with a two-stroke-cycle engine requires fuel that is a mixture of gasoline and oil. While this mixture is as stable as gasoline, I recommended that you not prepare more than you plan to use over a 4-5 month period. I treat all my stored fuel regardless of projected use with Sta-Bil or another gasoline preservative then use it within two years of treatment. Remember the gasoline-oil mixture should not ever be added to the fuel tank of a gasoline-fueled motor, always mix it in your storage containers unless unable to do so (in which case add the Sta-Bil first then fill the tank up to 95%).



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