How Long Can a Generator Sit Unused?
How long can your generator sit unused? Short answer: not long without trouble. Leave it idle too long and you'll be facing stale fuel, seized parts, or a dead battery. This article breaks it down—how long you’ve really got, how to store it right, and how to keep it ready for when the power cuts out.
The Hidden Dangers of an Unused Generator
Letting your generator sit untouched for weeks or months might seem harmless. But under the hood, things are quietly going downhill.
The Problem with Fuel Degradation
Fuel, especially ethanol-blended petrol like E10, starts to degrade within 30 days. Left untreated, it turns to varnish or sludge, clogging the carburettor and making your generator harder to start. In hot Aussie conditions, this process speeds up. If you’ve ever pulled the cord for five minutes with no response, you’ve likely met stale fuel.
Why Engine Parts Seize
Engines like to move. When your generator sits idle, the internal parts lose their lubrication. Over time, this can cause them to seize up—literally freeze in place. Think of it like leaving your bike out in the rain, untouched. Come summer, the wheels won’t turn without a fight.
The Dangers of Rust and Corrosion
Australia’s humidity, especially near the coast, is a silent killer. Moisture seeps into every crevice, rusting metal parts and corroding sensitive components. Salt air makes it worse. A rusted generator isn’t just ugly—it’s unreliable when you need it most.
How the Battery Drains
If your generator has an electric start, the battery won’t hold a charge forever. Left untouched, it gradually drains—even when the unit is off. Come storm season, you might find yourself with a perfectly good generator and a dead battery. A quick top-up every month can save a lot of swearing later.
Exercising Your Generator: The Key to Reliability
A generator isn’t like a fine wine—it doesn’t get better with age. Regular use is what keeps it ready to go.
Creating a Regular Maintenance Schedule for Your Generator
Set a recurring reminder on your phone or stick a note in the shed. Every two weeks, give your generator a short run. Regular exercise keeps the internals moving, the fuel system clean, and problems from building up unnoticed.
Why You Should "Exercise" a Generator
Running your generator every few weeks helps prevent fuel breakdown and keeps seals lubricated. It’s like taking your car for a spin after it’s been parked up for a while. Letting it idle occasionally helps the engine stay in good nick and avoids surprises down the track.
How Often and for How Long to Run Your Generator
Aim for 5–10 minutes every fortnight. It doesn’t need to be a full workout—just enough to keep it in shape. If it’s been stored for a while, let it run for a bit longer to ensure everything is functioning smoothly.
Running the Generator with a Load vs. Without a Load
Running your generator under load (e.g. plugged into a small appliance) is better than idling. It simulates real-world use and puts the electrical system to work. Just don’t overload it—stick to a modest draw like a fan or light.
Preparing Your Generator for Long-Term Storage
If you’re not planning to use your generator for a few months, it needs more than a dusty corner in the shed.
Fuel Management for Your Stored Generator
Leaving fuel in the tank is risky business. Ethanol-based petrol absorbs moisture and deteriorates quickly, especially in heat. You’ve got two options: drain it or stabilise it.
The "Drain It Dry" Method
For long-term storage, draining is best. Let the generator cool, shut off the fuel valve, and drain the tank and carburettor completely. This prevents gumming and protects the engine from moisture-related damage. Just make sure to run it dry, so no fuel is left in the lines.
The Best Fuel Stabilizer
If you plan to use your generator again within 6–12 months, a fuel stabiliser is your best mate. Brands like Penrite, STA-BIL, and Lucas work well. Mix it with fresh petrol, fill the tank, and run the engine for 10 minutes so it circulates through the system. This keeps fuel from breaking down and avoids clogs.
A Complete Checklist for Your Generator
Before storing your generator, tick off the following to ensure it's ready next time.
Changing Your Generator's Oil
Old oil can become acidic and damage internal parts. Change the oil before storage—especially if it’s close to the 100-hour mark. Use manufacturer-recommended oil and keep a spare bottle on hand. Clean oil means less risk of corrosion inside the engine.
Engine "Fogging" and Its Importance
For generators stored over winter, fogging oil adds a protective layer inside the engine. Spray it into the air intake while the engine is running, then shut it off. This helps prevent corrosion and dry starts when you fire it up again.
Storing Your Generator: Location and Environment
Pick a dry, cool spot with plenty of airflow. Avoid hot sheds or damp garages. If you’re near the coast, protect it from salty air—use a cover or store it indoors. And make sure pests can’t nest inside—mice love quiet engines.
Done right, storage doesn’t just preserve your generator—it guarantees it’s ready to go when you need it. Whether it’s a blackout, storm, or weekend away, a well-maintained generator is your silent insurance policy.
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