How to Store a Generator When Not in Use

Short-Term Storage (Under 30 Days)

If you're storing the generator for less than a month, minimal preparation is needed:

• Leave fresh gasoline in the tank — no stabilizer required for under 30 days.
• Ensure the generator is clean and dry before storing. Wipe down the engine and housing.
• Store in a dry location out of direct rain and extreme heat.
• If you used the generator outdoors in wet weather, check that no water has entered the fuel tank or air filter.

Medium-Term Storage (30 Days to 6 Months)

This is the most common storage scenario — storing the generator between seasons or between infrequent outages. The biggest risk here is fuel degradation.

Option 1: Stabilize the Fuel (Easier)

1. Fill the fuel tank completely. A full tank minimizes air space, reducing moisture condensation and oxidation.
2. Add fuel stabilizer at the manufacturer's recommended ratio (typically 1 oz per 2.5 gallons). STA-BIL, PRI-G, and Star Tron are common brands.
3. Start the generator and run it for 5–10 minutes to allow the stabilized fuel to circulate through the carburetor.
4. Shut down normally and store.

Stabilized gasoline is good for 1–2 years depending on the product. Label your fuel container with the date it was stabilized.

Option 2: Drain the Fuel System (More Thorough)

1. Run the generator until the fuel tank is low.
2. Turn off the fuel valve (if equipped) and let the engine run until it starves and stops on its own. This clears fuel from the carburetor bowl.
3. Restart and run again briefly to ensure the carburetor is empty.
4. Drain any remaining gasoline from the tank using a hand pump or by tilting (with care — never near ignition sources).

A dry fuel system cannot varnish. This method is more work but provides absolute protection against carburetor gumming during longer storage periods.

Battery Care (Electric-Start Models)

• A disconnected battery self-discharges over 3–6 months and may not hold sufficient charge to start the generator.
• For storage under 2 months, simply disconnecting the negative terminal is sufficient.
• For longer storage, use a battery maintainer/trickle charger. A quality float charger (Battery Tender, CTEK) will maintain the battery indefinitely without overcharging.
• If the battery is over 3 years old, test it before storing — replace if it won't hold a charge.

Long-Term Storage (6 Months or More)

Extended storage requires a more comprehensive approach to protect the engine from corrosion and the fuel system from degradation.

Step-by-Step Long-Term Storage Procedure

1. Change the oil. Used oil contains combustion byproducts including acids that corrode engine internals during storage. Fresh oil is the best way to prevent cylinder bore rust and bearing corrosion.
2. Drain or stabilize fuel as described above. For storage beyond 6 months, draining is strongly preferred.
3. Fog the cylinder(s). With the generator off, remove the spark plug(s), spray fogging oil into the cylinder(s), and slowly pull the recoil cord 3–4 times to coat the cylinder walls. Reinstall the spark plug(s). This prevents cylinder bore rust, which can cause hard starts and piston damage.
4. Clean the air filter. Remove and inspect; replace if dirty. A clean filter prevents insects from nesting inside the air box (a surprisingly common issue).
5. Disconnect and maintain the battery as described above.
6. Cover the exhaust port with a clean cloth or tape to prevent insects and moisture from entering.
7. Cover the generator with a fitted generator cover allowing air circulation. A breathable cover prevents moisture buildup better than a solid tarp.
8. Store in a cool, dry location. A garage or shed is ideal. Avoid direct sunlight, which degrades plastic components and fuel over time.
9. Label with the service date and storage date so you know what maintenance has been done when you retrieve it.

Where to Store a Generator

Generators should be stored outdoors or in a detached structure whenever possible due to fuel and CO risk. Here are the options ranked:

• Detached garage or shed: Best option. Keeps the generator dry and protected while keeping gasoline fumes out of living spaces.
• Attached garage: Acceptable if the generator is fully cooled and fuel is properly stabilized. Never store with a hot engine or in an enclosed space where fuel vapors can accumulate near a furnace or water heater igniter.
• Under a deck or carport: Acceptable with a weather cover as long as the area is well-ventilated and the generator is secured from theft.
• Inside a living space: Never acceptable. Gasoline vapors are explosive and generators present a CO risk even when not running (residual exhaust).
• Outdoors without cover: Not ideal — UV degrades plastics and rubber, and moisture accelerates corrosion. Use a UV-resistant generator cover at minimum.

Returning to Service After Storage

Before starting a stored generator, run through this checklist:

If the generator won't start after proper storage preparation, the most likely cause is a gummed carburetor (if fuel wasn't fully drained or stabilized). Carburetor cleaning with carb cleaner spray or ultrasonic cleaning resolves most cases without replacement.