Generator Fuel Stabilizer: When and How to Use

What fuel stabilizer does

Fuel stabilizer is an additive you mix into gasoline to slow down the chemical changes that happen as fuel sits. Over time, gasoline can break down, forming gums and varnish that may clog fuel systems. A stabilizer helps keep the fuel fresh for a longer period, which is useful if you store a generator between storms.

The product label on the stabilizer bottle tells you the correct ratio of stabilizer to gasoline. Follow that label exactly. The generator's owner's manual may also have instructions about fuel storage and additives; read it alongside the stabilizer label.

For Florida homeowners, keeping a generator ready for hurricane season means thinking about fuel freshness. The Florida Division of Emergency Management's generator safety page advises stocking fuel safely and reading the manual before a storm. Adding stabilizer is part of that preparation. See our best backup power for Florida guide for more on preparing your home.

When to add stabilizer

Add stabilizer to fresh gasoline before you fill the generator's tank or a storage container. Mixing it into fresh fuel is more effective than adding it later to fuel that has already started to degrade. If you plan to store the generator for more than a few weeks, treat the fuel at the time of filling.

For Florida hurricane season, the Florida Division of Emergency Management recommends stocking fuel safely and reading your generator's manual before a storm. Adding stabilizer is part of preparing your generator for long-term storage between outages.

If you use a fuel container, add the stabilizer to the container before you fill it with gasoline, or follow the product's instructions for mixing. Always store fuel in an approved container and keep it in a safe location as described by the maker. For generator options that fit your needs, check our best portable generators for hurricanes guide.

How much stabilizer to use

The amount of stabilizer depends on the product and the volume of gasoline. The label gives a ratio, such as ounces per gallon. Use a measuring device to get the right amount; guessing can lead to too little or too much additive.

Some stabilizers have a higher concentration for long-term storage. Read the label to see if it distinguishes between short-term and long-term storage, and follow the instructions for the length of time you expect to store the fuel.

After adding stabilizer, run the generator for a few minutes so the treated fuel reaches the carburetor and fuel lines. This ensures the stabilizer is throughout the fuel system, not just in the tank. The generator's manual may describe this process. If you're comparing generator types, our dual fuel generator guide explains fuel options.

Fuel shelf life and storage

Gasoline naturally degrades over time, but a stabilizer can extend its usable life. The exact shelf life depends on the fuel's composition and storage conditions. The stabilizer label often states how long it can preserve fuel, such as up to 12 or 24 months.

Store treated fuel in a cool, dry place, away from direct sunlight and heat sources. The generator's manual may specify a storage location and temperature range. Avoid storing fuel near ignition sources or in living areas.

The Florida Division of Emergency Management's generator safety page advises stocking fuel safely and reading the manual. For fuel storage regulations, check with your local authorities or the maker's guidance. For a generator that suits your storage space, see our best inverter generators for Florida neighborhoods guide.

Stabilizer and ethanol

Gasoline with ethanol can absorb moisture over time, which may lead to phase separation. Some fuel stabilizers are formulated to address ethanol-related issues. The product label will indicate if it is designed for ethanol-blended fuels.

If you use ethanol-blended gasoline, choose a stabilizer that states it is compatible. The generator's manual may also mention fuel recommendations. Follow both the manual and the stabilizer label for the best results.

This site does not provide fuel handling advice beyond what the maker and the product label state. For specific questions about ethanol and your generator, contact the generator's manufacturer. If you're considering a tri fuel generator, our tri fuel guide covers fuel flexibility.

What to check before storing

Before you store your generator for the off-season, review the owner's manual for the recommended storage procedure. The manual may include steps like draining the carburetor or running the fuel system dry, in addition to using a stabilizer.

The Florida Division of Emergency Management's generator safety page suggests cleaning the generator and storing it safely after a storm. This includes checking for damage and ensuring the unit is dry.

Keep the stabilizer bottle and the generator's manual together so you have the instructions when you need them. This is part of a good maintenance routine, as described in the manual. For a complete maintenance checklist, see our generator maintenance checklist article.

Safety and official sources

Fuel stabilizer is a chemical product; handle it according to the label's safety instructions. Keep it out of reach of children and away from flames or sparks. The label will list any precautions.

For generator safety, including fuel handling, the Florida Division of Emergency Management provides guidance on its generator safety page. The Consumer Product Safety Commission also publishes information about generator hazards. Read those pages and follow the maker's manual.

This article explains what fuel stabilizer is and how to use it as the label describes. It does not replace the manufacturer's instructions or official safety guidance. For more on choosing a generator, visit our best backup power for Florida guide.

What to pick for your situation

Questions

When should I add fuel stabilizer to my generator?

Add stabilizer to fresh gasoline before filling the tank or a storage container. This is most effective if you plan to store the generator for more than a few weeks, such as between hurricane seasons.

How much fuel stabilizer should I use?

Follow the product label for the correct ratio, usually ounces per gallon. Use a measuring device to get the right amount, and run the generator briefly after adding to distribute the stabilizer through the fuel system.

Does fuel stabilizer extend gasoline shelf life?

Yes, stabilizers slow down the degradation of gasoline, extending its usable life. The label often states how long it can preserve fuel, such as up to 12 or 24 months, depending on storage conditions.

Can I use fuel stabilizer with ethanol-blended gasoline?

Some stabilizers are formulated for ethanol-blended fuels. Check the label to ensure compatibility, and follow the generator's manual for fuel recommendations.

Where should I store treated fuel?

Store treated fuel in an approved container in a cool, dry place away from heat and ignition sources. The generator's manual may specify a storage location and temperature range.