Most generators sit for months, then get asked to run for hours with no warning, often in bad weather. The steps below are general, common-sense maintenance. Your owner’s manual is the authority on oil type, capacities, service intervals and the storage procedure for your model, so keep it with the generator.
Before you put it away
- Let it cool, then clean it. Wipe off dust and debris and keep the cooling vents and air intake clear.
- Handle the fuel the way your manual says. Manuals differ. Some say to run the carburetor dry or drain the tank; others say to fill the tank with fresh fuel and add a stabilizer. Either way, don’t leave old, untreated gas sitting in the engine.
- Check or change the oil. Fresh oil before storage is a common recommendation, so the engine isn’t sitting on used oil. Use the type and amount the manual lists, and check the level with the generator on level ground.
- Look at the air filter and spark plug. Clean or replace a dirty filter, and replace a worn or fouled plug.
- Store it dry and ventilated. Keep it away from furnaces, water heaters and anything with a pilot light, and cover it only after it has fully cooled.
Keeping it ready between outages
- Exercise it. Many manuals call for a short run on a regular schedule, often with some load connected, to keep the carburetor and seals in good shape. Follow your manual’s interval.
- Keep the battery charged on electric-start models, using a maintainer or periodic charging if the manual allows it.
- Inspect cords and outlets. Look for cut insulation, bent prongs and damaged plugs. Use outdoor-rated cords sized for the load.
- Keep a small kit together: the manual, a spare plug and air filter, oil, a funnel, and fresh fuel in an approved container. Our fuel storage guide covers keeping gas fresh.
- Log the hours. If your generator has an hour meter, write down each oil change so you know when the next one is due.
Safety reminders
Generator exhaust contains carbon monoxide, which you can’t see or smell. Run a generator outdoors only, well away from doors, windows and vents, and never in a garage, basement or enclosed porch, even with the door open. Keep a working carbon monoxide alarm in the house. Never plug a generator into a wall outlet; connecting it to home wiring requires a properly installed transfer switch or inlet, done by a licensed electrician. Shut the engine off and let it cool before refueling.
Frequently asked questions
How often should I run a stored generator?
It depends on the model. Many owner’s manuals recommend a short exercise run on a regular schedule, often monthly and with some load connected. Check your manual for the interval and procedure it recommends.
Should I drain the fuel or use a stabilizer?
Manuals differ. Some say to run the engine until it stops or drain the fuel system before storage; others say to fill the tank with fresh, stabilized fuel. Follow your generator’s manual.
When should I change the oil?
Follow the hour-based interval in your owner’s manual. Many owners also change the oil before long-term storage so the engine isn’t sitting on used oil.
Can I run a generator in the garage with the door open?
No. Carbon monoxide can build up quickly in enclosed or partly enclosed spaces. Run the generator outdoors, well away from doors, windows and vents.
AMSOIL products for generator storage
- AMSOIL Gasoline Stabilizer. AMSOIL says it “keeps fuel from deteriorating during storage for up to 12 months, allowing easier startups” and lists generators among its applications. AMSOIL also says it “eliminates the need to drain fuel from equipment before long-term storage.” If your generator’s manual says to drain the fuel, follow the manual.
- AMSOIL Engine Fogging Oil. AMSOIL calls it a “highly-effective rust preventive designed to protect internal engine components during storage or long periods of inactivity” and lists portable generators among its applications. AMSOIL’s directions: “Consult equipment owners manual for application directions.”
Product wording above is quoted or summarized from amsoil.com. Read each product’s label and data sheet for directions.
Engine oil type and viscosity depend on your generator’s engine. Check your owner’s manual, then use AMSOIL’s official lookup guide to see what AMSOIL lists for your equipment.