How to store a generator long term (so it starts next time)

The short version

1. Under a month: nothing special. Honda says no preparation is needed.
2. One to two months: fresh gas plus fuel stabilizer, then run it a few minutes so treated fuel reaches the carburetor.
3. Two months to a year: stabilized fuel, and drain the carburetor or run it dry.
4. A year or more: drain the tank and carburetor, change the oil, and oil the cylinder.
5. Every time: let it cool, store it upright, and keep it away from flames and pilot lights.

Makers don't all agree, so check your own manual. The differences are below.

Why storage matters so much

Gas doesn't keep. Honda's manual says fuel can deteriorate and oxidize "in as little as 30 days." Old gas causes hard starting and leaves gum that clogs the fuel system. Honda adds that its warranty doesn't cover fuel system damage "resulting from neglected storage preparation."

The carburetor is the weak spot. Champion says gas in the carburetor "WILL obstruct and clog the carburetor" if it isn't used or drained within two weeks. That's why a generator put away with old gas often won't start, or only runs on choke.

Fuel stabilizer or run it dry?

Both work. They protect different parts, so for longer storage most makers use both.

• Stabilizer slows the breakdown of gas in the tank. Champion says tank fuel can last "up to one year" with a properly formulated stabilizer, stored cool and dry. Briggs & Stratton says its own stabilizer keeps fuel fresh for up to 24 months.
• Running dry empties the carburetor, where gum does the most damage. You close the fuel valve with the engine running and let it stop on its own.
• Draining empties the tank and carburetor completely, so there's nothing left to go stale.

What each maker says

Maker (model)	Short storage	Long storage
Honda (EU2200i)	1–2 months: fresh gas + stabilizer. 2 months–1 year: also drain the carburetor bowl	1 year+: drain tank and carburetor, change oil, oil the cylinder
Champion (all gas and dual fuel)	Up to 1 year: stabilizer, run 10 minutes, fuel valve off, run until it stops	Over 1 year: tank and carburetor "must be completely drained"
Generac (portables)	Add stabilizer from the start	Over 30 days: drain the tank and run the carburetor dry
WEN (56250iX)	Drain the carburetor after each use and before storage	Over 60 days: drain tank and carburetor, change oil

Two details are easy to miss:

• Champion's stabilizer dose. Its storage bulletin says to add stabilizer at "2-3 times the manufacturer's recommended amount." Champion's manual also warns that only a few stabilizers are made to work with ethanol blends.
• WEN's monthly run. WEN says to "run the generator for at least 15 minutes every month," and never to keep fuel in the tank for more than two months.

Step by step: storing it for a season

This follows Champion's short-term steps, which line up closely with Honda's. Do it outdoors, where you'd normally run it.

1. Unplug everything.
2. Add stabilizer to the gas in the tank, at the dose on the bottle or in your manual.
3. Run it for about ten minutes so treated fuel reaches the carburetor.
4. Turn the fuel valve OFF with the engine still running. Let it run until it stops from lack of fuel. That usually takes a few minutes.
5. Turn the engine switch OFF and let it cool completely.
6. Change the oil if it's due.
7. Clean it. Honda says to wipe it with a damp cloth. Then put a light film of oil on bare metal that could rust.
8. Store it as described below.

Step by step: a year or more

Do the steps above, then:

1. Drain the tank and carburetor into an approved gas can. Honda drains the tank with a hand pump, saying not to use an electric pump. Then it drains the carburetor through its drain screw. Champion and WEN use the drain bolt on the carburetor bowl.
2. Change the oil.
3. Oil the cylinder. Remove the spark plug and pour in a little clean engine oil. Honda uses about a teaspoon (5 cc). Champion uses about a tablespoon. Crank the engine slowly a few times to spread it, then refit the plug.
4. Close the valves. Honda says to pull the starter grip slowly until you feel resistance, then let it back gently. This closes the valves "so moisture cannot enter."

Fuel work: engine off and cool, outdoors, no flames or sparks. Wipe up spills right away.

Where to store it

• Away from flames and heat. Champion says not to store the generator, gas or a propane cylinder near furnaces, water heaters or anything with an automatic ignition. Honda adds clothes dryers and areas with spark-producing motors or power tools.
• Well ventilated, if there's fuel inside. Honda says to choose a well-ventilated spot to reduce the risk of fuel vapors igniting.
• Upright and level. Honda says tilting it or laying it on its side can cause fuel or oil leaks.
• Dry. Honda says to avoid humid spots, which promote rust. Champion says a cool, dry place out of direct sunlight.
• Covered, but only when cool. Honda says a hot engine can ignite or melt a cover. It also warns against plastic sheets, which trap moisture.
• Vent and fuel valve closed. Unless the fuel is drained, Honda says to leave the engine switch OFF and the fuel cap vent OFF.

Storing a generator in a garage or shed is not the same as running it there. A cool generator in storage is fine. A running one never is: see can you run a generator in a garage.

Storing it outside? Honda warns that if a generator is stored outdoors without protection from the weather, you should check the control panel before each use. Moisture or ice can cause a short circuit that could electrocute you.

Spare gas belongs in an approved, labeled container, stored outside your living areas, NFPA says.

The starter battery

Electric-start models have a battery that drains in storage. Champion says to charge it fully at least once a month, at no more than 1.5 amps, and notes a float charger will keep it topped up over long storage. For long storage, Champion says to turn the ignition, fuel valve and battery switch off, and to disconnect the battery leads.

Getting it out of storage

1. Refill with fresh gas if you drained it.
2. Check the oil and the air filter. Champion says to clear out bugs and cobwebs.
3. Open the fuel valve with the engine off, and check for leaks after a few minutes. Champion says a leak means the carburetor needs cleaning or replacing.
4. Start it with nothing plugged in.

A short puff of smoke at startup is normal if you oiled the cylinder. Honda says so. Lots of smoke isn't: see generator smoking. If it starts but gives no power, see generator running but no power.

Run it outdoors only, 20+ feet from the house, away from windows and doors: generator carbon monoxide safety.