A generator that isn't maintained is a generator that won't start when the power goes out. The good news: keeping one in good shape takes about an hour a year if you follow a simple schedule. Here's exactly what to do and when.
Weekly (Automatic Standby Generators Only)
Most standby generators run a self-test automatically — typically a 10–20 minute exercise cycle once a week. You don't need to do anything, but you should listen for it. If your unit stops running its weekly test, that's usually a sign of a battery issue or a fault code worth checking.
- Listen for the weekly exercise cycle
- Check the control panel for any fault codes or warning lights
- Visually inspect for oil leaks, rodent nests, or debris around the unit
Before Each Use (Portable Generators)
Portable generators sit idle for months between uses. Before you pull the cord:
- Check the oil level — use the dipstick; oil should be at the full mark. Low oil is the number one cause of engine damage.
- Check the fuel — old gasoline degrades in as little as 30 days without a stabilizer. If the fuel is more than a month old, drain and replace it.
- Inspect the air filter — a clogged filter causes hard starting and poor performance. Clean or replace if dirty.
- Check the spark plug — look for fouling or corrosion. Replace if the electrode is worn.
Every 100 Hours or Annually (Whichever Comes First)
This is the main service interval for most residential generators, whether portable or standby. According to manufacturer guidelines from leading brands, annual service should include:
- Oil change — use the viscosity grade specified in your owner's manual (commonly SAE 10W-30 for most residential units). Dispose of used oil at a certified recycling facility.
- Oil filter replacement — replace at every oil change
- Air filter inspection and replacement
- Spark plug replacement — even if the plug looks okay, annual replacement is cheap insurance
- Fuel filter inspection (if equipped)
- Battery test (standby units) — batteries typically last 2–3 years; test voltage under load
- Coolant level check (liquid-cooled units only)
- Tighten all connections — vibration loosens fasteners over time
Every 2 Years
- Replace the battery on standby units proactively — don't wait for a failure
- Inspect and clean the spark arrestor (portable units used near dry vegetation)
- Check transfer switch contacts for arcing or corrosion (standby units — have a licensed electrician inspect)
Seasonal Prep: Before Storm Season
In the Northeast, the highest-risk outage period runs from late summer through winter. Before hurricane season or the first major storm of the season:
- Run the generator under load for at least 30 minutes to verify it performs correctly
- Top off fuel and add a fuel stabilizer if storing more than 30 days
- Test the transfer switch by cutting shore power manually and confirming the generator picks up the load
- Stock spare oil, filters, and spark plugs so you're not hunting for them during an outage
- Clear debris and vegetation from around the unit — maintain at least 3 feet of clearance on all sides for airflow
What Voids a Warranty
Most residential generator warranties require documented annual service by a qualified technician. Skipping service or using non-approved oil grades can void coverage. If your unit is under a manufacturer warranty, confirm service requirements in your documentation before doing your own maintenance.
When to Call a Pro
DIY maintenance covers oil, filters, plugs, and visual inspections. Call a licensed electrician or generator service technician for:
- Transfer switch inspection or replacement
- Control board or fault code diagnosis
- Fuel system repairs (standby units on natural gas or propane)
- Any work inside the electrical panel
Our full maintenance guide covers each of these topics in more detail. Questions? Contact us and we'll point you in the right direction.
Sources
- U.S. Consumer Product Safety Commission — Portable Generator Safety. cpsc.gov
- U.S. Department of Energy — Generators. energy.gov
- OSHA — Portable Generator Hazards. osha.gov