Whether it’s to power your home during unexpected outages or support off-grid living, generators are indispensable assets. For many homeowners, opting for used home generators for sale presents a cost-effective solution without compromising performance. However, to get the best value and long-term reliability from a used generator, proper maintenance is key.
In this blog, we’ll delve into the best maintenance practices to extend the lifespan of your used generator, ensure safe operation, and maintain optimal performance. Whether you’re a first-time buyer or a seasoned user, these tips will help keep your generator running efficiently for years to come.
Why Maintenance Is Crucial for Used Generators
Unlike new units, used home generators have a history of operation that may include wear and tear, variable usage patterns, and environmental exposure. Maintenance helps mitigate these factors and prevent minor issues from becoming expensive repairs.
By maintaining your used generator:
- You prevent breakdowns during critical times (like storms or blackouts).
- You preserve fuel efficiency and operational safety.
- You increase the system’s resale or trade-in value.
- You comply with local code or insurance requirements in some jurisdictions.
Let’s explore the essential maintenance steps to help you get the most from your used generator.
1. Establish a Regular Inspection Routine
Create a checklist for visual and mechanical inspections every 1–3 months or after every 20–50 hours of use, depending on your usage pattern. During inspections:
- Look for fuel or oil leaks around gaskets and hoses.
- Check for corrosion on terminals and bolts.
- Inspect belts, fans, and wiring for signs of wear.
- Confirm that warning lights and display indicators are functioning.
Regular inspections can help you catch issues early, reducing repair costs and downtime.
2. Change Oil and Oil Filters Regularly
Oil changes are arguably the most important part of generator maintenance. Dirty or old oil leads to friction, overheating, and long-term engine damage. For used home generators, it’s even more critical since their internal parts have already experienced wear.
Recommended schedule:
- After the first 20–30 hours post-purchase (for used units).
- Then every 100 hours of operation or at least annually.
- Always change the oil filter when changing the oil.
Use manufacturer-recommended oil types and filters, especially for brands like Generac, Kohler, or Briggs & Stratton.
3. Keep the Battery in Top Condition
One of the leading causes of generator startup failure is a depleted or malfunctioning battery. If your used generator came with a battery, test it regularly and replace it if it’s more than 2–3 years old.
Battery care tips:
- Clean terminals and apply anti-corrosion gel.
- Check electrolyte levels if it’s not maintenance-free.
- Use a battery maintainer or trickle charger for standby units.
4. Replace the Air and Fuel Filters
Clogged air or fuel filters can severely reduce efficiency and increase strain on the engine. Replace air filters every 200–250 hours or annually. Fuel filters may need changing more frequently if you’re using diesel or poor-quality fuel.
Pro tip: Always inspect filters during scheduled oil changes to streamline your maintenance routine.
5. Run Your Generator Periodically
Generators that sit idle for months can suffer from dried gaskets, stale fuel, and corrosion. To avoid this, run your generator for 15–30 minutes every month. This helps circulate oil and keep internal parts lubricated.
When running:
- Use at least a 50% load to simulate real-world operation.
- Listen for unusual sounds or vibrations.
- Monitor exhaust color—blue or black smoke can indicate internal issues.
6. Use High-Quality Fuel and Fuel Stabilizers
Fuel quality greatly impacts generator performance. Ethanol-based gasoline, in particular, can degrade quickly and damage carburetors. For standby generators:
- Use ethanol-free gas when possible.
- If you plan to store fuel for longer than 30 days, consider using a fuel stabilizer to maintain its quality.
- Drain and replace fuel every 6–12 months if the generator is unused.
In diesel generators, microbial growth (“diesel bugs”) can contaminate fuel. Use biocide additives and filter fuel before storage.
7. Perform a Load Bank Test
A load bank test helps confirm whether your used generator can handle the rated electrical load. This is especially important for commercial or whole-house systems.
Why it’s important:
- It helps burn off carbon deposits in the engine.
- Verifies operational performance under real conditions.
- Identifies potential failure points before emergencies.
Experts recommend performing a load bank test once a year, particularly if your generator runs infrequently.
8. Understand the Purpose of Megger Test
When maintaining electrical systems within a generator, conducting a Megger test is a valuable diagnostic procedure.
What is the purpose of Megger test?
A Megger test (or insulation resistance test) measures the insulation quality of electrical wires and windings within the generator. Over time, insulation can degrade due to moisture, age, or mechanical damage.
The purpose of Megger test includes:
- Detecting insulation breakdown that could cause short circuits or electrocution.
- Preventing internal electrical fires.
- Ensuring the generator complies with safety standards before operation.
Conduct this test annually or when transferring ownership of a used unit. Always hire a licensed technician to perform Megger testing, especially on larger generators.
9. Clean the Generator and Enclosure
Dust, grime, and rodents can all contribute to performance issues. Keep your generator clean by:
- Wiping down the exterior monthly.
- Cleaning intake/exhaust vents to prevent overheating.
- Installing rodent-proof mesh if the unit is stored outdoors or in a garage.
Make sure the generator is turned off and cool before cleaning. Avoid using a pressure washer or water hose unless specified by the manufacturer.
10. Keep Records of Service and Repairs
Maintain a detailed service log including:
- Dates of oil changes, battery replacements, and filter swaps.
- Megger test results and load bank performance data.
- Notes on technician visits and diagnostics.
This log will be helpful for resale, warranty claims, and troubleshooting future issues. If you’ve recently purchased from a dealer offering used home generators for sale, ask for maintenance records to better understand its condition.
11. Schedule Annual Professional Inspections
While DIY maintenance is great for routine care, a yearly professional inspection ensures all system components—from alternators to transfer switches—are working properly. Professionals can spot things you might miss, like:
- Voltage fluctuations.
- Bearing wear in alternators.
- Exhaust leaks.
- Starter motor inefficiencies.
This annual check-up is especially important for used generators, as small issues may have gone unnoticed by previous owners.
No Power No Problem: Your Generator Partner in the Midwest
At No Power No Problem, we specialize in keeping your generator dependable, whether it’s brand-new or gently used. We understand the importance of safe, continuous power in your home — especially during emergencies.
We proudly offer a selection of used home generators for sale, each inspected, serviced, and tested by our certified technicians. Our customers trust us for:
- Comprehensive maintenance plans
- Emergency 24/7 generator repair
- Megger testing and load bank analysis
- Service coverage across Michigan, Ohio, and Indiana
With strategic locations in Wixom, Grand Rapids, and Dayton, we’re never too far when your generator needs attention. As your peace-of-mind partner, we’re committed to powering your home and keeping your family protected — no matter what.
Conclusion
Investing in a used generator is a smart move — but only if you treat it with the care it deserves. By following the maintenance tips outlined above, you can extend the lifespan of your generator, improve efficiency, and ensure it performs when you need it most.
From routine oil changes and Megger tests to professional inspections and quality fuel use, maintenance is the key to maximizing your investment. Whether you’re maintaining your own unit or shopping among used home generators for sale, always prioritize safety, reliability, and service.
And remember — when in doubt, call the pros. At No Power No Problem, we’ve got your back 24/7.